Observables in constructive empiricism

Constructive empiricists such as Bas van Fraassen hold that we should take our best scientific theories not to be true but merely empirically adequate, where a theory is empirically adequate when what it claims about observable phenomena is true. We should believe what our best theories tell us about the observable world, but remain agnostic about any unobservable phenomena they postulate. For the constructive empiricist, something is observable just in case it can in principle be detected by the unaided senses. So we should be agnostic about electrons, mitochondria, the strong nuclear force, the tricarboxylic acid cycle, etc.

Obviously, the cogency of constructive empiricism depends on whether the observable/unobservable distinction can be made to work. Van Fraassen treats observability as a property of entities. Some types of entities are such that they produce certain changes in our perceptual systems, provided we have the right kind of relation to them; these entities are observable. For example, Jupiter's moons are observable. From Earth, of course, we require telescopes to detect them, but they are in principle detectable with the unaided senses because we could travel to them, and then they would impinge on our senses in certain ways. So van Fraassen isn't agnostic about Jupiter's moons; he believes they exist.

The question is, how should the "in principle" be interpreted? What kind of relation to an entity is the "right" kind of relation? Van Fraassen, as far as I know, is fairly dismissive of this kind of problem. He thinks that "observable" is a vague predicate so there is no precise distinction between the observable and the unobservable, but this is no threat to constructive empiricism because even with a vague boundary we can still specify entities that are unambiguously unobservable. It seems to me, however, that without an answer to those questions, it isn't at all clear that there are any unambiguously unobservable entities - or at least, that the class of them becomes so small that constructive empiricism fades into realism.

Van Fraassen is happy to count distant astronomical objects such as quasars as observable, because we would detect them unaided if we travelled billions of light-years in their direction. Similarly, past entities such as dinosaurs are observable, because we would detect them unaided them if we went back into the past. The observable is not just what is detectable unaided given current technology, as Jupiter's moons are. We can also imagine technology that violates the laws of physics, that can take us millions of years into the past or billions of light-years distant.

There are various problems with this treatment of observability, but the constructive empiricist in particular surely can't accept it. Once we're allowed to imagine totally speculative technology, we might say that in principle I could see a bacterium with my unaided senses, because I could enter a miniaturization machine and be shrunk down to the bacterium's size. Indeed, it's worth noting that miniaturization appears to be more plausible than travelling to the most distant quasars, since miniaturization doesn't violate any laws of physics as far as I'm aware. So on this view, a whole host of phenomena become observable and the distinction between constructive empiricism and realism fades. One fix is to say:

(A) The observable is what is detectable with the unaided senses given current technology, here in 2017.

But now consider the situation for astronomers working, say, 300 years ago. Given the technology at the time, both Jupiter's moons and bacteria were equally inaccessible. It later turned out that space travel was feasible whereas miniaturization was not, but surely there was no justification available in the 1700s for expecting technology to develop that way. If we accept (A), then the constructive empiricist has the curious conclusion that, in the 1700s, it was reasonable to believe in Jupiter's moons even though there was good reason to think that Jupiter's moons were unobservable in the same way that microbes were unobservable.

A similar problem arises when we consider future technological developments. Maybe we will in fact develop miniaturization machines and people will directly interact with microbes. If observability is determined by current technology, then microbes will still count as unobservable and therefore our miniature descendents should remain agnostic about microbes. With these points in mind, it seems we have to drop (A) in favour of:

(B) The observable at time t is what is detectable with the unaided senses given the technology at t.

However, technology can regress. If a nuclear holocaust occurs and we lose our ability to construct telescopes, then Jupiter's moons will become unobservable again. The constructive empiricist would have to conclude that we must once again be agnostic about the existence of Jupiter's moon. To avoid this conclusion we can modify (B):

(B*) The observable at time t is what is detectable with the unaided senses given the technology at t and any time before t.

This doesn't seem to face any obvious problems. However, an interesting consequence of (B*) is that it can be used to strengthen the case against the constructive empiricist by supporting an "optimistic induction" argument for realism about unobservables. This is because (B*) allows that unobservable entities can become observable as technology develops. Briefly, the argument is that numerous entities postulated by our best theories were initially unobservable but later became observable, thus vindicating those believed in such entities; so we can similarly expect that those who believe in currently unobservable entities will be vindicated in the future if the technology develops to make those entities potentially observable.

Jupiter's moons were once unobservable. Over the past few decades we have sent machines to Jupiter, and we could probably even send a person there, though that might be a waste of time and money. In any case, Jupiter's moons clearly do exist. The astronomers of the past who believed in these objects have been vindicated. Numerous other examples can be found from astronomy: (a) Other planets and moons and their properties. We can now see directly that the Moon's surface is disfigured by craters, that Venus undergoes phases similar to the Moon, that Mars has a tenuous carbon dioxide atmosphere, etc. (b) The true properties of the Sun, such as its size and sunspots. (c) The asteroid belt. (d) Comets. (e) Certain properties of the gravitational force. We feel a particular gravitational force on the surface of the Earth; now we can ascend to space in rockets and directly feel that the force is lesser there. (f) The shape of the Earth: predicted to be an oblate spheroid on theoretical grounds, its shape can now be directly seen.

Of course, this is an inductive argument, and van Fraassen rejects induction. However, as far as I can tell, this is not a necessary feature of constructive empiricism. In any case, anybody who accepts induction has an additional reason to be wary of constructive empiricism.

Philosophy of extraterrestrials: an unfairly neglected subject

Philosophers have devoted very little attention to the subject of extraterrestrial life. Cirkovic, Kukla, and Lamb are the only recent philosophical monographs on the subject that I'm aware of. The lack of philosophical engagement with the extraterrestrial question is puzzling for several reasons:

(1) As is demonstrated by Dick and Crowe, there is a long history of philosophical discussion of extraterrestrials. The early atomists were optimistic about extraterrestrials. They proposed an infinitely large universe, consisting solely of "atoms and the void", with different arrangements of atoms producing the diversity of objects we see around us. On this view, our planet and the organisms inhabiting it were created by chance collisions of atoms. Given this metaphysics, we can expect that other worlds with other living creatures will have arisen elsewhere. Lucretius, for example, says (quote taken from Kukla):

it is in the highest degree unlikely that this earth and sky is the only one to have been created … This follows from the fact that our world has been made by nature through the spontaneous and causal collision and the multifarious, accidental, random and purposeless congregation and coalescence of atoms whose suddenly formed combinations could serve on each occasion as the starting-point of substantial fabrics – earth and sea and sky and the races of living creatures.

Following the Copernican revolution, the scholarly discussion of extraterrestrial life snowballed, and optimism was the dominant position. There were two primary justifications for belief in extraterrestrials. First, most scientists accepted the Copernican Principle, which claimed, to put it simply, that there is nothing special about the Earth (versions of this principle are still accepted today). The stars are suns just like our own; and all areas of the universe are subject to the same laws of nature. Thus it was expected that planets similar to the Earth would be prevalent throughout the universe. Studies of other solar system bodies seemed to confirm the similarity to the Earth: astronomers observed clouds on Jupiter and mountains on the Moon. Second, abundance of extraterrestrial life was held to follow from religious commitments. God would not be wasteful; he would not have created a vast universe filled with stars and planets for no reason. Obviously such other worlds were not created for the benefit of humankind, so their purpose must be to house other intelligent species. Many scholars, such as William Herschel, went as far as to suggest that the Moon, the comets, Saturn's rings, and even the interior of the Sun, were inhabited.

Against this optimism were those who held that extraterrestrial life, even if it does not explicitly contradict anything in the Bible, is at least in some tension with a religion that is structured around humanity's unique experience and history. Should we suppose that Jesus died and was resurrected on an infinite number of planets? This seems absurd. Or perhaps extraterrestrials have not fallen and so are in no need of redemption? But now we are supposing that the Earth is uniquely evil. Along with these religious concerns, by the mid-1800s scholars such as William Whewell were emphasizing scientific studies showing significant differences between the planets, such as spectroscopic studies of the Moon that revealed its lack of appreciable atmosphere. Philosophers engaged in a great debate about extraterrestrials throughout the 19th century.

(2) The scientific study of extraterrestrial life, which is part of the field of astrobiology, is a highly interdisciplinary field currently undergoing rapid progress, however its conceptual foundations have yet to be fully developed. For exmaple, what is the status of principles such as the anthropic principle and the aforementioned Copernican principle, and how should they be applied? How much can we learn from the Drake equation? So far, much of this work has been left to the scientists themselves. Philosophical study of extraterrestrials will allow philosophers to work closely with an increasingly powerful science, and on a topic that is of great interest to many people even outside of academia.

(3) The problem of extraterrestrials is connected with a variety of topics in philosophy of biology, philosophy of language, philosophy of mind, ethics, and so on. For example:

-- One of the first questions that arises in the search for extraterrestrial life is, what exactly are we looking for? What is life? This is, of course, a central problem in philosophy of biology.

-- Assuming that life does exist on other planets, how similar should we expect it to be to life on this planet? There has been a great deal of debate in philosophy of biology about the degree to which the evolutionary process is contingent, or is instead driven by trends that tend to produce convergence on the same solutions. A similar question is, does civilization require a humanoid form? Dolphins, octopi, and crows are intelligent animals, but it's difficult to see how they could build a civilization due to the limits of their morphologies - they simply cannot manipulate tools in the precise ways that humans hands can.

-- A number of authors have suggested that SETI is in some sense unscientific. To take Popper's criterion of falsifiability, for example, it seems that SETI research is organized around a proposition that is unfalsifiable, namely: there exist detectable extraterrestrial civilizations. SETI may therefore provide a good case study for discussion of the demarcation problem of how to distinguish science from non-science.

-- Putting aside the practical problem of the vast distances, is it possible even in principle to communicate with extraterrestrials? Translating human languages, such as Egyptian hieroglyphics, is often hard enough; the difficulties facing any interpreters of extraterrestrial signals will be orders of magnitude greater. Is there anything that could serve as a "universal langauge" - mathematics, for example? (I discuss the problem of extraterrestrial communication in this video.

-- Active SETI is a branch of SETI that attempts to contact extraterrestrials directly by sending messages into space. Various authors have argued that while listening for extraterrestrials is acceptable, we should refrain from sending messages ourselves because it poses potentially catastrhopic risks. We don't know the character or the capabilities of the civilizations we are attempting to contant. For all we know, they may well be able to do us great harm. (I discuss these risks in this video.

-- What will be the impact on our culture of discovering extraterrestrial life? Are contemporary religions such as Christianity compatible with the existence of extraterrestrials?

-- We may well discover simple microbial life elsewhere in the solar system; Mars and Europa, for example, remain possible abodes of life. What moral obligations would we have to such life? What kind of planetary protection policies should we adopt? How can we extend contemporary theories in environmental ethics to cover extraterrestrial life?


Why did philosophers lose interest in extraterrestrials? I don't have the historical competence to answer this definitively, but it's worth noting a few points. By the early 1900s, the scientific justification for belief in extensive extraterrestrial life had collapsed. Closer studies of the other planets of the solar system revealed them to be barren, desolate worlds, wholly unsuitable for life. The "canals of Mars" controversy had brought disrepute to the study of extraterrestrials. Furthermore, by this time the dominant view of the origin of the solar system was the Chamberlin-Moulton encounter hypothesis, which proposed that the solar system formed when another star passed close to the Sun and gravitational interaction drew out huge filaments of material that coalesced to form the planets. Planets were therefore likely to be extremely rare. Whereas the Copernican revolution had initially seemed to provide a scientific basis for optimism, extraterrestrials now once again entered the realm of mere speculation.

At around the same time, philosophy became dominated by the logical positivists, who held that philosophy cannot make empirical claims and instead focused on technical problems of meaning of scientific terms, theory reduction, the nature of scientific confirmation, etc. They saw little value in philosophical speculation on grand topics such as extraterrestrials. In later decades, into the 1940s and beyond, outlandish reports of UFOs and alien abductions have sullied the topic of extraterrestrials still further in the eyes of serious philosophers.

Whatever the reasons for the absence of philosophical study of extraterrestrials, I hope, in light of the great scientific progress on the problem and the wide range of philosophical issues it connects with, that more philosophers turn their attention to it in the near future.

Entity realism and experimental failure

Entity realism, defended most famously by Ian Hacking, is the view that we should be sceptical of scientific theories, but we should believe in unobservable entities that scientists can manipulate and use as tools to study other phenomena. Nobody will ever observe an electron, but we should believe in electrons because we can spray them onto deuterium to help study weak neutral currents. As Hacking says, "When we use entities as tools, as instruments of inquiry, we are entitled to regard them as real."

Discussions of entity realism often assume that experimental or manipulative success is the entity realist's criterion for belief in unobservable entities; Gelfert, for example, says: "In its original form due to Ian Hacking, entity realism postulates a criterion of manipulative success which replaces explanatory virtue as the criterion of justified scientific belief." I suggest that the entity realist would be better off dropping this criterion. Experimental failure often provides just as strong reason for belief as experimental success.

Consider the following case from solar astronomy. Thermonuclear fusion in the core of the Sun occurs by the proton-proton chain, where four protons are converted into a helium nucleus, two positrons, and two electron neutrinos:

4p → ⁴He + 2e⁺ + 2ν_e

Neutrinos interact with matter extremely rarely; a piece of lead one light-year thick would stop only 50% of any neutrinos passing through it. The vast majority of neutrinos produced in thermonuclear fusion pass straight through the Sun unimpeded. So studying neutrino flux gives us a direct view into the core of the Sun. The challenge is how to detect the flux of these particles that interact so weakly with matter.

The first experiment to detect solar neutrinos was developed in the mid-60s by Ray Davis using a tank of perchloroethylene, C2Cl4. Very rarely, a neutrino collided with a chlorine nucleus, converting it into radioactive argon by converting a neutron into a proton. The radioactive argon was then captured by bubbling helium through the tank. Davis used the rate of argon production to measure the neutrino flux. Unfortunately, the Davis experiment was a failure; he detected only 1/4 of predicted neutrino flux (figures are from Longair's The Cosmic Century, p.180):

Predicted flux: 7.9 +/- 2.6 solar neutrino units
Observed flux: 2.1 +/- 0.9 solar neutrino units

What went wrong? Different reactions in the p-p chain produce electron neutrinos of different energies. It was proposed that Davis was detecting only the high-energy neutrinos. Further experiments, such as GALLEX and SAGE, which were based on neutrino collisions converting gallium into radioactive germanium, were designed to detect the low-energy neutrinos. These experiments also failed; they detected only about half of the predicted low-energy neutrino flux. Another suggestion was that something was wrong with the solar models – perhaps we were mistaken about the temperature in the core of the Sun, for example – however, by the 90s experiments in helioseismology were providing robust confirmation of these models, and it became clear that the problem lay with our understanding of the nuclear physics relating to neutrinos (see Longair p.182).

The problem was finally resolved in the early 2000s by the discovery of neutrino oscillation: some of the electron neutrinos produced in the p-p chain spontaneously converted into tau and muon neutrinos, which were not detected by any of the original experiments. However, what is interesting in the context of entity realism is the situation in the decades prior to this. From the mid-60s to the early-00s, across numerous different experiments, predictions failed and experiments did not work as intended. So any argument from experimental success could not apply to neutrinos. Yet it remains the case that scientists used neutrinos as tools, as "instruments of inquiry", in their investigations of the core of the Sun, which seems to be what Hacking requires to justify belief in neutrinos. Indeed, few, if any, scientists working on solar physics doubted that neutrinos were being detected.

This case suggests that there is nothing especially important about experimental success. By analogy, we use hammers to drive nails into walls. There are many ways we might fail: we might smash a hole in the wall, or we might be using a dud nail that snaps when we hit it. None of this would lead us to doubt the existence of the hammer. We don't infer the hammer's existence from its success at driving nails into walls; the fact that we can use and manipulate the hammer in certain ways is enough.

One reason why it's worth exploring cases of experimental failure is that these may provide the entity realist with the resources to answer the persistent objection that entity realism collapses into standard scientific realism. Believing in some entity X, so the objection goes, requires believing theories about X. As Alan Musgrave puts it:

To believe in an entity, while believing nothing else about that entity, is to believe nothing or next to nothing. I tell you that I believe in hobgoblins. "So", you say, "You think there are little people who creep into houses at night and do the housework." To which I reply that I do not believe that, or anything else about what hobgoblins do or what they are like - I just believe in them.

Hacking, as is well known, has claimed that while we shouldn't believe scientific theories about e.g. electrons, there are basic "home truths" about electrons, a basic "common lore" about electrons, that we should all accept. Such home truths include that electrons have negative charge, that they "orbit" (in some sense) atomic nuclei, that they have a rest mass of about 9.1x10-31kg, that certain materials transmit electrons more readily than others, etc. This is enough to give us a substantial belief in electrons, and to allow us to use electrons in scientific experiments.

Theories change but home truths remain. This is illustrated very nicely by the neutrino experiments. Since the neutrino detection experiments failed to confirm the theoretical predictions, it was clear that some part of the theory was wrong. Initially this was attributed to inaccuracies in the solar models, but by the 1990s most scientists turned their attention to the nuclear physics. Neutrino theory was wrong. Arguably then, belief in neutrinos could not be justified by appealing to this theory. Nevertheless, scientists retained certain low-level assumptions or "home truths" about the causal powers of neutrinos, such as that neutrinos are produced by reactions in the p-p chain, and that they can very occasionally collide with chlorine converting it into argon. Perhaps entity realists should turn their attention to examples of experimental failure.

An interesting follow-up question for the entity realist would be, how do we distinguish cases of failed prediction where we nevertheless assume that the experimenters were using a certain unobservable, as occurred in neutrino astronomy, from those cases where we think that nothing important was detected? Joseph Weber's research into gravitational waves might be an example of the latter case.

Quine on unactualized possibilia

I'd like to examine some arguments from Quine's On What There Is, one of the most famous papers in modern philosophy. In particular, I want to focus on Quine's comments concerning the Platonic riddle of nonbeing.

As Quine puts it: "Non-being must in some sense be, otherwise what is it that there is not?" In asserting, for instance, "Pegasus does not exist", I appear to commit myself to the existence, or to the being, of Pegasus. What is it that I'm saying doesn't exist? If Pegasus is nothing, then when we use the word "Pegasus", we're not talking about anything, which would render any statements containing the word nonsensical. "Pegasus does not exist" would amount to "_ does not exist". So, Pegasus, along with other nonexistent things, must have being of some sort, in order to account for the intelligibility of our discourse about nonexistents.

We might formalize the argument like so:

(P1) If "Pegasus" names nothing, then statements about Pegasus are nonsensical.
(P2) Statements about Pegasus are not nonsensical.
(C) So, "Pegasus" must name something.

Another way to see the problem is that it would appear that, if "Pegasus" and "Santa Claus" name nothing, than "Pegasus does not exist" and "Santa Claus does not exist" are each saying exactly the same thing. In each case, we're referring to nothing, and saying it doesn't exist.

(P3) If "Pegasus" names nothing and "Santa Claus" names nothing, then "Pegasus does not exist" and "Santa Claus does not exist" both say the same thing.
(P4) "Pegasus does not exist" and "Santa Claus does not exist" do not say the same thing.
(C) "Pegasus" and "Santa Claus" must each name something.

"Pegasus" names something, but what? One option is to hold that Pegasus has a kind of being as an unactualized possible object (Quine attributes this view to a character called "Wyman"). Reality consists of existent, actual objects; and also various nonexistent, merely possible objects.


Quine's objections to unactualized possibilia

1. First, how do we individuate such entities? What are their conditions of identity? The moment we try to analyze possible objects in any detail, we find that we can't answer simple questions about them:

Take, for instance, the possible fat man in that doorway, and, again, the possible bald man in that doorway. Are they the same possible man, or two possible men? How do we decide? How many possible men are there in that doorway? Are there more possible thin ones than fat ones? How many of them are alike? Or would their being alike make them one? Are no two possible things alike? Is this is the same as saying that it is impossible for two things to be alike? Or, finally, is the concept of identity simply inapplicable to unactualized possibles? But what sense can be found in talking of entities which cannot meaningfully be said to be identical with themselves and distinct from one another?

2. A second objection, related to the first, not explicitly stated by Quine but I think implicit in his paper, is that due to the problem of individuating possible objects, postulating possible objects doesn't actually solve the problem of referring to non-existent things. For if we can't individuate possible objects, we can't ever know what is being referred to when people use the term "Pegasus".

I don't think Wyman should be too troubled by these first two objections. In the first place, over the last few decades very detailed theories of modal metaphysics have been worked out that make answering questions such as these perfectly straightforward. Consider, for instance, Lewis's modal realism. Lewis would deny that there is a possible fat man in that doorway. Rather, at some possible world, a fat man is standing in the counterpart of that doorway. At some other possible world, a bald man is standing in the counterpart of that doorway. At some other world, a fat, bald man is standing in the counterpart of that doorway; at some other world, two fat, bald men are standing in the counterpart of that doorway; etc. Re whether any two possible men are alike, we evaluate the similarity of different possible objects in just the same way we evaluate the similarity of actual objects. Re identity, again, this is essentially just the same as for actual objects. (This is not to suggest that Lewis's theory, or any other realist theory of possibilia, is particularly plausible. But I think that Wyman could appeal to such developments to defuse Quine's objection.)

Second, as Richard Routley argues in his paper "On What There Isn't", precisely the same sort of difficulties arise for existing objects. Routley parodies the passage from Quine:

Take, for instance, the cloud in the sky above; and again, the adjacent cloud in the sky. Are they the same cloud or two clouds? How are we to decide? How many clouds are there in the sky? Are there more cumulus than nimbus? How many of them are alike? Or would their being alike make them one? ... is the concept of identity simply inapplicable to clouds? But what sense can be found in talking of entities which cannot meaningfully be said to be identical with themselves and distinct from one another?

Perhaps Routley isn't entirely fair here - surely there must be more difficulties with possible objects, if only because possible objects are so much more extensive, and include many stranger things, than actual ones - but the basic point is, I think, correct: just because it turns out to be difficult to answer seemingly simple questions about a certain class of objects, it hardly follows that we have reason to believe that there are no such objects. Reality is full of strange, difficult things. It's also full of perfectly straightforward things that turn out to be puzzling when subjected to certain questions, as when we try to come up with clear criteria for individuating clouds.

3. The notion of a possible object rests on a confusion. Modality, Quine suggests, applies to whole sentences, not to particular things. "It is possible there is a man in the doorway" is perfectly acceptable, the possibility in this case attaching to the sentence "there is a fat man in the doorway"; but it's illegitimate to infer from this to "there is a possible man in the doorway", with the possibility attaching to an entity, the fat man. (Quine doesn't present his reasoning for this in this paper. His arguments here are complex and I won't go into them here. I did start a video series on this, which I never got around to finishing. Michael Morris's An Introduction to Philosophy of Language also covers it.)

Quine suggests that the main motive for expanding possibility from sentences to objects is to deal with the riddle of nonbeing. I'm not convinced. I suspect that the main motive is the problem of explaining what the truthmakers of modal sentences are. The Nazis could have won WWII, I could have become a research chemist, nothing can exceed the speed of light, Frank couldn't have done any better in the exam, etc - in virtue of what, exactly, are such sentences true? Positing possible worlds is one way to deal with this.

4. Even putting aside the above problems, Wyman's account is simply incomplete. The postulation of unactualized possible objects doesn't help at all when we consider terms that apparently refer to impossible objects, such as "the round square cupola on Berkeley college". Quine suggests that one option for Wyman would be to hold that such terms are meaningless. So, regarding our riddle of nonbeing:

(P1) If "round square" names nothing, then statements about round squares are nonsensical.
(P2) Statements about round squares are not nonsensical.
(C) So, "round squares" must name something.

Wyman could reject (P2), accepting that "round square" names nothing and hence that statements about round squares are meaningless. Quine has two objections to this move. First, he argues, the claim that statements about round squares are meaningless "has no intrinsic appeal"; i.e. it's an unattractive and ad hoc hypothesis proposed simply to save the theory. Now, I'm not sure I agree with Quine here. To me, at any rate, "round square" does indeed seem to be meaningless, in some important sense. Of course, I can use the phrase "round square"; and I know what round things are and I know what square things are, so I might think that I'm able to make some inferences about what properties we might attribute to a round square. On the other hand, when I try to think about it in any detail, it slips out of my grasp. Can I really make inferences about it? Here's an easy one: it's a square, and square things have four sides, so it must have four sides. But this just ignores that we're talking about a round square. Round things don't have any sides.

It may be objected that "round square" is obviously contradictory, and this is why we struggle to assign any meaning to it. Sometimes however contradictions are disguised. Only on analysis do we realize that a proposed object is contradictory. Consider the suggestion that God, at least as conceived in Western monotheistic traditions, is contradictory, re arguments that properties such as omnipotence and omniscience lead to irresolvable paradoxes. Even if the atheist is correct about this, it's still the case that people have been able to talk about God in detail, and structure their lives around their belief in God, and even believe that they can have a personal relationship with God. Surely then we can't insist that the concept of God is simply meaningless.

There are two ways Wyman might deal with this. First, he could simply bite the bullet. Any concept that can be shown to entail contradictions is thereby meaningless. This is not such a radical position. The logical positivists held that a statement is meaningful only if it's analytically true or empirically verifiable; with this criterion they attempted to show that a whole host of apparently meaningful statements aren't meaningful after all, including statements about God (see e.g. Ayer's Language, Truth and Logic, chapter 6). Our ability to talk about God, to hold detailed religious beliefs, etc, can be explained by appealing to meaning in a weaker sense, e.g. emotional or poetic meaning. "Colourless green ideas sleep furiously" has no literal meaning, but we might say that it's meaningful in some extended, metaphorical sense.

Second, Wyman could reduce the force of the problem by suggesting that some contradictions are possible. Consider contradictory objects like the Penrose triangle or Penrose stairs.

Are these impossible? Round squares are simply inconceivable and can't be intelligibly talked about, but staircases that keep going up without ever getting higher can actually be visualized. By allowing that some contradictions are possible, Wyman significantly reduces the number of apparently meaningful statements he has to consign to meaninglessness. Of course, this option genuinely would be radical, but the ground has been prepared by dialetheism and paraconsistent logics.

Quine's second objection to the suggestion that statements apparently about impossible objects are meaningless is that this "makes it impossible, in principle, ever to devise an effective test of what is meaningful and what is not." Quine says: "it follows from a discovery in mathematical logic, due to Church, that there can be no generally applicable test of contradictoriness." I assume that what Quine actually has in mind is Gödel's second incompleteness theorem, which demonstrates, essentially, that any consistent formal system cannot prove its own consistency. So put simply: if contradictory objects are impossible, and statements about impossible objects are meaningless, then since there's no test for determining contradictoriness, there's no test for determining meaninglessness.

I have two comments about Quine's objection: (a) Why exactly do we need a strict, systematic way of determining what's meaningful? Why wouldn't it be good enough just to have a few basic rules of thumb? (It's not as though Quine is any stranger to indeterminacy of meaning!) (b) Again, Quine's criticism evaporates if Wyman severes the link between possibility and consistency, and holds that contradictory objects can be possible. Then he doesn't need to say that all contradictory statements are meaningless. In which case, it doesn't follow from the fact that there can be no effective test of what's contradictory that there can be no effective test of what's meaningful.

Ultimately then, it seems to me that rejecting (P2) is a much more plausible move than Quine suggests. Let me make one final comment here. Another obvious option for Wyman is simply to accept both (P1) and (P2), and draw the conclusion that there are unactualized impossibles, in just the same way as there are unactualized possibles. Quine objects to this move that if Wyman admits unactualized impossibles, then he will be trapped in contradictions. But why would this trouble Wyman? After all, he's openly admitting impossibles. Why wouldn't he also admit that some of those impossibles are contradictory?

5. Fifth, Quine suggests that the puzzle of nonbeing rests on a confusion between meaning and naming. Consider again (P1) and (P3):

(P1) If "Pegasus" names nothing, then statements about Pegasus are nonsensical.
(P3) If "Pegasus" names nothing and "Santa Claus" names nothing, then "Pegasus does not exist" and "Santa Claus does not exist" both say the same thing.

These claims seem to rest on the assumption that the meaning of a name is simply is referent (called direct reference theory or Millianism). If names have meanings above and beyond their referents, then "Pegasus" can be perfectly meaningful despite failing to refer to anything (and "Santa Claus" can also be perfectly meaningful, and can mean something different from "Pegasus", despite failing to refer). But Millianism has been subjected to a number of serious objections. Quine appeals to the famous problem of "Frege's Puzzle". Consider the following propositions:

(1) The Morning Star is the Morning Star.
(2) The Morning Star is the Evening Star.

"The Morning Star" and "the Evening Star" both refer to the same object, namely Venus, which on Millianism seems to entail that the phrases have exactly the same meaning. Now, if "the Morning Star" and "the Evening Star" have the same meaning, then we should be able to substitute one for the other in a sentence without changing the meaning of the sentence, which entails that (1) and (2) have the same meaning. But surely this isn't right: (1) is simply trivial, whereas (2) is interesting and informative; (1) is a tautology, whereas (2) tells us something important about the world; (1) is knowable a priori, whereas it takes hands-on empirical investigation to confirm the truth of (2).

I don't have anything to say about this point. I agree with Quine that Millianism isn't adequate, and that if Millianism goes, the justification for (P1) and (P3) is undermined.

6. Finally, Quine appeals to Occam's Razor. Admitting unactualized possible objects massively expands our ontology without good reason. Quine thinks there's an alternative, more ontologically parsimonious solution to the riddle, which appeals to Russell's theory of descriptions. I won't discuss Quine's own solution here. I only note here that the view that there exist, or there are are in some sense unactualized possibilia, has a variety of motivations (cf. Lewis again). Quine's appeal to Occam's Razor is rather less convincing if we have to accept possibilia anyway for other reasons.

Richard Routley - Is There a Need for a New, an Environmental, Ethic?

In this famous 1973 paper, Routley attacks anthropocentrism and argues that ethics should recognize the intrinsic value of various nonhuman or even nonsentient items. ("Intrinsic" is intended to contrast with "instrumental".)

Anthropocentrism, the standard Western ethic

First, Routley discusses the traditional anthropocentric ethical tradition, and identifies three different strands of this tradition: (1) despotism: this views humans as the rulers of nature, so that humans have dominion over nature and can with it whatever they please; (2) stewardship: humans are the custodians or protectors of nature; (3) cooperation: humans are the perfectors of nature, with a duty to transform it into a more perfect state.

(1) is clearly unacceptable, but (2) or (3) prima facie seem better suited to an environmental perspective. However, Routley objects that both (2) and (3) "imply policies of complete interference", and hence are incompatible with environmentalism. I'm not convinced of this, especially with the notion of stewardship. Whether or not stewardship implies interference depends on what we take to be valuable; it depends on what exactly it is that we're trying to protect. I assume it's true that historically, stewardship views have called for a transformation of nature: nature is wild, having been put there by God to be perfected and developed by man, and ideally all of nature will be so developed. Seen in this way, the stewardship view and the environmental view will come into conflict. But nothing in the basic idea of stewardship implies anything like this.

Stewardship emphasizes responsible use. Even if our only concern is humans, there's obviously nothing responsible in pursuing a policy of "complete interference". Complete interference is clearly a bad move because interfering with ecosystems, even with a goal to "improving" them, has all sorts of unforeseeable consequences. There are substantial parts of the natural world that should be protected and, importantly, largely left alone. So Routley's objection to (2) misses the mark (as we'll see in the next section, he later offers a more powerful objection to (2), and all other anthropocentric approaches).

We can identify the core principles of an ethic. Any ethic that rejects one or more of the core principles of the standard Western ethic is a new ethic. Routley suggests that one of the core principles of the standard Western ethic is the "liberal principle":

The liberal principle: "One should be able to do what he wishes, providing (1) that he does not harm others and (2) that he is not likely to harm himself irreparably" (where "other" is of course intended to mean "other human" or, on recent animal rights ethics, perhaps "other sentient being").

Routley thinks that our moral judgements concerning the environment outstrip what can supported by the liberal principle. The liberal principle should be rejected, and that means that a new ethic is required.

Against anthropocentrism

Routley gives a number of examples that he takes to demonstrate the failure of the liberal principle:

(1) The last man: Imagine a man who has survived the collapse of society and the death of all other people. For some reason, perhaps just to pass the time until he dies or to take his mind off the loss of all his friends, he decides to go about destroying, as far as possible, every living thing and every item of value. On an environmental ethic such destructive behaviour is deplorable, but it's totally permissible on an anthropocentric ethic. Indeed, an anthropocentric ethic might even recommend it - for instance, if the Last Man finds his behaviour very satisfying and pleasurable, then an anthropocentric utilitarianism would recommend that he continue (since his pleasure is all that matters).

(2) The last people: Imagine a society who know that they're the last people, for instance because the effects of radiation have prevented any chance of reproduction. Since they're the last people, there's no longer any need to protect the environment for future generations, so they vastly accelerate production and consumption, putting all land under intensive cultivation, stripping away all the rainforests, farming all the fish out the seas, etc. Again, on an environmental ethic this destructive behaviour is deplorable, but it's totally permissible, perhaps even recommended, on an anthropocentric ethic. After all, they're simply doing what they can to improve their own lives before their inevitable extinction. If this vastly increased consumption spells disaster for the environment - well, who cares? No future people will be around to be negatively affected by it.

Routley also gives the examples of (3) the last man is an entrepreneur who damages the environment in pursuit of greater productivity and (4) the extermination of the blue whale to extract its oil and meat. I won't discuss these cases as (3) is a minor variation of (1) and (4) can, I think, be quite easily accommodated by standard ethical views. Even from an anthropocentric perspective the destruction of species is a bad idea for various reasons, including that they might be of significant scientific value, that they might play important roles in the ecosystems on which humans depend for their resources, etc. Also note that animal rights views would similarly condemn (4), but Routley wants to extend moral considerability not just to animals but also to nonsentient or even nonliving things. Scenarios (1) and (2) present the best case for this. Of course, animal rights views would similarly condemn the killing of sentient beings in (1) and (2), but we can simply modify the scenarios so that in (1) all other sentient beings save the Last Man are dead, and in (2) all other sentient species save humans are dead.

It's worth considering more carefully the structure of Routley's argument. First he identifies a moral principle that he takes to be at the core of Western ethics - the liberal principle. Then he offers a scenario in which this principle permits certain environmentally damaging actions that intuitively we consider morally impermissible on environmental grounds. Routley thinks that this necessitates the development of a new ethic that rejects the liberal principle and assigns intrinsic moral worth to various nonsentient or nonliving items. Let's try to formalize the argument:

(P1) The liberal principle is a core principle of standard Western ethics.
(P2) If the liberal principle is true, then forests have no intrinsic moral value.
(P3) If forests have no intrinsic moral value, then the Last Man's actions are morally permissible.
(P4) The Last Man's actions are not morally permissible.
(C1) Forests have intrinsic moral value.
(C2) The liberal principle is false.
(C3) Standard Western ethics must be rejected.

(Readers who, like myself, hold that moral claims aren't truth-apt can simply substitute e.g. "acceptable" and "unnacceptable" for "true" and "false".)

Responses

I will now consider three ways of defending the standard ethic. The first accepts Routley's conclusion about the worth of nature but rejects (P1), challenging his characterization of the standard Western ethic; the second attempts to show, contra (P3), that our condemnation of the Last Man's actions is compatible with an anthropocentric ethic; the third challenges (P4) and the underlying methodology of Routley's argument.

Reject (P1)
Routley claims to be offering a new ethic. But how new is it really? (We have already seen one form of this objection in my discussion of the stewardship position. Arguably, stewardship is not as inimical to environmentalism as Routley suggests. However, I think it would struggle to account for the judgement that the actions of the Last Man and the Last People are wrong.) According to Routley, one of the core principles of the Western ethic is the liberal principle: reject the liberal principle, and you reject Western ethics.

However, it's very questionable whether the liberal principle is in fact a core principle. Consider the traditional objections to homosexuality. For most of the history of Western society, homosexuals have been imprisoned or worse. This seems very much at odds with a principle allowing us to do as we wish providing we don't harm ourselves or others. Of course, perhaps some of the objections to homosexuality were based on this principle, since many people argued, indeed many people still argue, that homosexuality is harmful. There are physical harms of spreading disease (the association of homosexuality with AIDS) and "spiritual" harms in that God disapproves and will perhaps send you to a place of eternal punishment. However, I doubt that the persecution of homosexuals really had much to do with a worry that they might be harming themselves or others.

For a more modern example, consider incest. Incest is punishable by imprisonment in many enlightened Western nations. As with the persecution of homosexuals, this seems very difficult to reconcile with the liberal principle. Again, people do suggest that incest is harmful in various ways, but such arguments are clearly weak, ad hoc rationalizations. The real objection to incest, just like the real objection to homosexuality, has nothing to do with concerns about harm. The real objection is "ewwww, that's gross" (see this video for my arguments that incest is morally permissible).

A number of similar examples can be found in the work of Jonathan Haidt and his colleagues (e.g. Haidt, Koller, and Dias's article "Affect, Culture, and Morality"). Consider the following scenarios: (a) a woman cuts up her country's national flag and uses it to clean her bathroom; (b) a family's dog is killed in a car accident; the family hear that dog meat is tasty so decide to eat it; (c) a man who is about to hold a dinner party has sex with a dead chicken, which he then cleans thoroughly, cooks, and serves to his guests. Most people hold that these actions are morally wrong and perhaps even should be prevented if possible. Yet the scenarios are constructed to rule out the possibility of harm, and indeed people have great difficulty identifying a source of harm.

On the other hand, one notable thing about subjects who are then asked to justify their judgements is that they tend to search for harms (e.g., abusing the flag might erode respect for one's country, threatening social harmony; having sex with a dead chicken involves risks of disease; etc). This suggests that people's moral reasoning, if not their immediate moral intuitions, is guided by the liberal principle. But the point here is that our actual judgements, however we might try to justify those judgements, don't seem to conform to the liberal principle. In which case, it's very questionable whether this principle should be considered an essential core of Western ethics.

Reject (P3)
Can standard Western ethics condemn the Last Man? Must we attribute intrinsic moral value to e.g. forests to conclude that the Last Man's destruction of the forests is morally wrong? Here's an obvious response: what makes it wrong to destroy all life is that this destroys the potential for future sentient or rational life. There's nothing intrinsically valuable about a forest. But on a planet rich in life there's far more potential for a new sentient or rational species to emerge than there is on a barren planet. This kind of response would be especially attractive to classical utilitarians. If moral behaviour is simply a matter of doing what we can to maximize happiness or pleasure, it's easy to explain the wrongness of the Last Man's actions. The Last Man should try to promote the emergence of new sentient beings, or if there's nothing he can actively do to promote this, he should at least refrain from preventing it.

Our scenario can however be modified. Consider:

(1a) Imagine a man who has survived the death of all sentient beings. He decides to go about destroying, as far as possible, every living thing and every item of value. Furthermore, in 100,000 years, the Sun will die, so there's not enough time for new sentient life to evolve.

If we hold that the Last Man's actions are morally wrong in this case, we rule out the suggested response. Of course, one worry here is that with the scenario modified in this way, I expect that fewer people will be inclined to judge that his actions are wrong (we will return to this point when we consider rejecting (P4)).

A second response is to argue that the Last Man is in some sense harming himself. Virtue ethics might provide a basis for this. On traditional Aristotelian virtue ethics, for instance, the goal of human life is eudaimonia, which translates essentially to happiness or fulfillment or well-being, and we achieve eudaimonia by cultivating a virtuous character (classically, a virtuous character involves the virtues of temperance, practical wisdom, justice, and courage). Importantly for this context, virtues directly benefit the individual: the virtuous person has a better life, a more fulfilling life, than the vicious one, even if the virtuous has fewer possessions, fewer friends, achieves fewer goals, etc. Although ethics is usually taken to concern our behaviour towards others, on virtue ethics the good life is entirely in line with your own self-interest. Just because the Last Man is alone, it doesn't mean that no ethical questions arise for him.

Against this background, we might argue that the destructive behaviour of the Last Man evinces a vicious character. Following Robert Sparrow (see his "The Ethics of Terraforming"), two possible vices in the Last Man's character are: (1) aesthetic insensitivity, a kind of blindness to beauty; and (2) hubris, an excessive pride/arrogance or glorying in one's own powers, often exhibited when a person ignores their proper limits. The Last Man is both blind to the elegance and beauty in the world, and has a vastly inflated view of his own importance. He doesn't evince the appropriate respect and humility towards nature. From the perspective of virtue ethics, he's only harming himself; the wrongness of his actions lies in the fact that they evince a vicious character, a character incompatible with his achieving eudaimonia. Ask yourself: would you want to be the Last Man? Would you want to be the sort of person who chooses to spend his last days vandalizing everything of beauty? Regarding these points, I'm reminded of this lovely quote from Simon Blackburn:

If we visit the Grand Canyon and I am overawed by its grandeur, while you see it just as a good place for tourist concessions, then I may well think less of you. And if I learn that one day I shall become like you, I would be depressed and ashamed, just as I would if I learned that one day I might lose my love of my children, or my concern for truth. I may voice this by saying that the canyon demands the reaction of wonder. But of course it doesn't issue any demands - indeed its ageless, implacable, indifferent silence is part of what makes it sublime. It is we who demand these reactions from ourselves and others, and rightly so.

However, I'm not convinced that this response works in the present context, for two reasons. First, arguably virtue ethics itself is simply incompatible with the liberal principle, which emerged out of deontological and consequentialist approaches to ethics (indeed, virtue ethics is often seen as providing an "anti-theoretical" approach to ethics, emphasizing the messiness and imprecision of our ethical lives and hence resistant to any strict ethical principles). So even if this response undermines Routley's argument against the liberal principle, it's far from clear that it's consistent with a defence of the liberal principle. Virtue ethics may itself represent a "new ethic".

Second, recall that the point of this response is to show how even if the natural world has no intrinsic value, the Last Man's behaviour might still be morally wrong. The problem is that I very much doubt that negative evaluations of the Last Man's character really make much sense without supposing the natural world to be of intrinsic value. Why, exactly, does his destruction of the forests exhibit an insensitivity to beauty, and an inappropriate hubris? If the natural world is only valuable insofar as it has uses for humans, the Last Man may well object that he's simply doing what any of us would: using the natural world in the ways he thinks are best. In his view, he says, barren landscapes are far more beautiful than lush rainforests. And there are no more humans to answer to, so what's the problem?

Reject (P4)
(P4) says that the Last Man's actions are not morally permissible. Routley doesn't bother to defend this claim; evidently, he assumes it's simply obvious that we should condemn the Last Man's actions. But is this obvious? Well, I suspect that such pointlessly destructive behaviour would make most people rather uneasy, although as far as I know no empirical studies testing the common person's reaction to Last Man scenarios have ever been done. But let's grant that, at least intuitively, the Last Man's behaviour is wrong.

Recall the broad structure of Routley's argument. It has essentially three parts: (a) the liberal principle permits action X; (b) but intuitively, X is impermissible; (c) so the liberal principle must be rejected. This kind of argument - attempting to demonstrate that particular moral principles entail unacceptable conclusions - is fairly standard in moral philosophy. But as the famous phrase goes, one man's modus ponens is another's modus tollens. Rather than rejecting the principle, we may reason as follows: (a) the liberal principle permits X; (b) intuitively, X is impermissible; (c) so, our intuitions about X are wrong.

What we have here is a clash of intuitions. Intuitively, X is wrong. But intuitively, the liberal principle is right, and the liberal principle permits X. From this point of view, it's at least as reasonable to reject (P4) as it is to accept it. In fact, the problem for Routley is even more serious than this, for two reasons. First, the liberal principle arguably has more to recommend it than mere intuitive support. It's part of the core of much of our moral reasoning (Routley surely wouldn't deny that; after all, he identifies the liberal principle as the core of Western ethics). It has the virtue of simplicity, and it provides us with a straightforward way of resolving moral and legal dilemmas. Furthermore, if we reject it, we face the question of what exactly we replace it with, and note that Routley doesn't offer any specific proposals in his article.

Second, basic moral principles tend to be fairly resistant to counterexamples. Consider the resistance of utilitarianism to apparently outrageous conclusions. Utilitarianism seems to entail that we must give enormous amounts of money to charity, perhaps even to the extent that we won't be able to afford any luxuries for ourselves. The good that would be done by buying yourself a luxury, say a Grateful Dead t-shirt or a nice meal restaurant, is vastly outweighed by the good that would be done by using that money to help save starving children. So, it's morally wrong to buy a Grateful Dead t-shirt. You should only buy clothes you really need, and send the money you save away. This conclusion is outrageous. But many people who are attracted to utilitarianism simply bite the bullet and reject the intuition that there's nothing wrong with spending your money on luxuries.

Why shouldn't the defender of the liberal principle simply reject the Last Man intuition? Indeed, this response seems especially plausible in the present case. The Last Man scenario is outlandish. It's an extreme case, totally removed from the normal context of moral judgement. How much weight should we place on our intuitions about a case like this? It's not surprising that we can develop extreme scenarios in which there's a mismatch between our general principles and our specific judgements. Bear in mind that Routley is, by his own admission, pushing for a radical change in our moral attitudes - not just a modification of existing ethics, but a wholesale revolution. A few troublesome intuitions about strange scenarios that are almost certainly never going to happen is a rather weak basis for such a lofty goal.

I should note that despite my critical comments, I largely agree with Routley. I think that forests, salt marshes, mountains, oceans, etc are intrinsically valuable; I completely reject human chauvinism. However, I'm not so sure about how to argue for this. These "deep green" commitments are simply part of the foundations, the core, of my worldview. There may be rhetorical value in Last Man examples, and if you're inclined to think that the Last Man's behaviour is morally wrong, then I'd encourage you to consider deep green ethics. But ultimately, for committed human chauvinists, I think there are very plausible responses to Last Man cases.

This concludes the main parts of the paper. I'll also make some comments about Routley's discussion of rights.

Rights

If we accept an environmental ethic, must we say that e.g. trees have rights? No, says Routley: the mere fact that there are moral prohibitions against acting a certain way towards an object doesn't entail that the object has rights; i.e. just because it's morally wrong to clear-cut a forest, doesn't entail that the forest has a right not to be clear-cut.

Of course, this depends on just how we're using the term "rights". But I agree with Routley that on many uses of that term, there's no reason why assigning intrinsic value to natural items would entail assigning rights to them. On one popular view of rights, noted by Routley, rights are coupled to responsibilities and obligations; obviously, it would be absurd to hold that trees, salt marshes, mountains etc have any responsibilities or obligations. It's clear that on this view, moral prohibitions extend beyond objects to which rights are assigned. For instance, there is a moral prohibitions against killing babies, but if rights entail responsibilities then babies don't strictly speaking have rights.

Another popular view is that rights are in some sense inviolable. If P has a right not to be killed, it would be wrong to kill P even if killing P would e.g. improve the general utility. Now evidently, we also have plenty of duties towards others that aren't inviolable. I should return the money you lent me, unless I discover that you intend to use the money to finance terrorism. I should not steal, unless my children are literally starving. It's easy to proliferate examples like this.

So it can be perfectly reasonable to say that it's morally wrong to clear-cut a forest, that we have certain obligations towards the forest, without the forest thereby having rights (perhaps because if the circumstances were different, it would be acceptable to clear-cut the forest).

Beckerman and Pasek - In Defense of Anthropocentrism

One of the central projects of environmental ethics is to displace anthropocentrism, the view that only humans are intrinsically valuable, and legitimize the attribution of intrinsic value to the natural environment. B&P take "intrinsic" to contrast with "instrumental". An object is intrumentally valuable if it's valued for its contribution to some other objective; an object is intrinsically valuable if it's valued for its own sake, for no further reason. On an anthropocentric ethic, then, the environment is valuable only instrumentally, only for the uses that humans can make of it.

B&P note that there are two ways of understanding value. On the objectivist view, value exists independently of the judgements of valuers. Value inheres in the world in a similar way to e.g. mass or charge. The subjectivist, by contrast, holds that values can't exist without a valuer. Things are right or wrong, good or bad, because we interpret them that way.

B&P's concern in this paper, they say, is with the question: can the environment bear intrinsic value? Given their title, one would expect that their answer is "no". I'm not sure that this is their answer, however. Their arguments are directed towards denying objective intrinsic value. As B&P themselves note, nothing stops a subjectivist from holding that certain natural items are intrinsically valuable. It's worth being clear about the distinctions involved as in my experience this often causes confusion. Ethics is concerned with what objects have value; an anthropocentric ethic claims that humans are the only objects of value, or at least the only objects of intrinsic value (things that are of use to humans may be valuable instrumentally). Metaethics is concerned with the source of value (what is value? how is value realized in the world? etc); an anthropocentric metaethic claims that humans are the only source of value, i.e. to say that something is valuable is to say that it's valued by some human.

Importantly, an anthropocentric metaethic doesn't entail an anthropocentric ethic. Consider, for instance, crude emotivism, according to which value judgements don't describe the world but simply express feelings. "Abortion is wrong" means something along the lines of "boo to abortion!"; "charity is good" means something along the lines of "yay for charity!" This is clearly anthropocentric about the source of value, i.e. it's an anthropocentric metaethic. Is an emotivist committed to an anthropocentric ethic? Of course not. The emotivist may value e.g. biodiversity just for its own sake. She may, that is, attribute intrinsic value to biodiversity.

What B&P are attacking, then, is not the view that parts of environment are intrinsically valuable, but rather the view that this intrinsic value is objective. They are concerned with metaethics, not ethics. This makes some of their arguments rather odd, since they attack arguments for nonanthropocentric ethics.


They first consider the Last Man Argument proposed by Richard Routley, later Richard Sylvan. Routley imagines a man, the last man on the planet, who has survived the total collapse of civilization and the death of all other people. This man decides to destroy, as far as he can, all living things and all beautiful natural items. Routley thinks it's clear that the Last Man's actions are deplorable, but on an anthropocentric ethic, it's hard to explain why this is so. After all, if only humans matter, the only reason why destroying non-human things is a problem is that other humans might object, and obviously no other humans are objecting to the Last Man's actions. Routley takes his thought experiment to show that the natural environment is also of intrinsic value.

B&P's objection to the Last Man Argument is bizarre:

Suppose that after the last man has departed, leaving behind the mountains and trees, and so on, perhaps in due deference to their intrinsic value and beauty, some aliens from outer space arrive on earth one day who have very different tastes from ours. They much prefer flat surfaces and find all these mountains and trees sticking up all over the place to be very ugly. Any philosophers among them who had previously espoused the "last man" argument would be looking rather silly.

First, it's unclear what this is supposed to show. The aliens don't share our environmentalist orientation. So what? Perhaps the aliens have all sorts of repugnant beliefs. They might support slavery, for instance. Would this show anything about our views of slavery? In any case, there are already plenty of people on this very planet who reject the environmentalist attitude, preferring a world wholly transformed by technology (the sensible ones would grant that it's not a good idea in practice, at least not currently, given that we depend on various processes in the environment for our survival, but they'd have no objection in principle to e.g. completely stripping away the forests and replacing them with plastic trees). All this tells us is that people have different moral and aesthetic attitudes, something that's already perfectly obvious to everyone.

Second, an obvious problem for B&P, given that they're concerned with denying that the natural world has objective intrinsic value, is that Routley's argument isn't supposed to establish objective intrinsic value. Routley is simply arguing that the natural world is intrinsically valuable; his paper is completely tangential to the question of whether this value is objective or subjective. Indeed, Routley wasn't an objectivist. (He wasn't quite a subjectivist either. He developed a rather bizarre metaethical position, inspired by his Meinongian metaphysics, according to which to say that some state of affairs X has value is to say that X is valued by a person at some possible world; this person may or may not exist in the actual world. In other words, things can have value because they are valued by a non-existent, merely possible person. Yet another way to put it is to say: X is valuable because X would be valued by a person if that person were to exist.)

B&P haven't paid sufficient attention to the distinction, discussed above, between the source of value (metaethics) and the object of value (ethics). As I explained, we can hold that the source of value is wholly anthropocentric without holding that the only objects of value are humans. B&P's oversight in this respect is odd given that they draw attention to the distinction earlier in the paper.


B&P also charge that prominent defenders of the objective intrinsic value of nature are in fact beholden to human interests and values. First they consider Arne Naess's statement as part of the deep ecology platform that "Richness and diversity of life forms ... are also values in themselves. Humans have no right to reduce this richness and diversity except to satisfy vital needs." B&P point out that these vital needs are, of course, the vital needs of humans. How this is supposed to be an objection to Naess is a mystery. After all, Naess doesn't deny that humans have a right to flourish; indeed he explicitly affirms that they do. He simply holds that other species and ecosystems have that right as well. This is completely consistent with also holding that sometimes, in conflicts of interest between humans and nonhumans, the humans win. Naess's statement is therefore analogous to "individuals have no right to harm others except in self-defense." Affirming that humans have the right to flourish, that the good of non-humans can be sometimes sacrificed for humans, doesn't entail that one is really a disguised anthropocentrist - just like how affirming that each individual has the right to flourish, that the good of other people can sometimes be sacrificed for the good of the individual, doesn't entail that one is really a disguised egoist.

Next they quote Sylvan & Bennett (1994): "there should be no substantially differential treatment of items outside any favoured class or species of a discriminatory sort that lacks sufficient justification." B&P object that it is humans, of course, who must decide what counts as sufficient justification. So again, the attempt to attribute objective intrinsic value to nature just leads us back to humans as the basis of value. B&P say: "we are once again relying on humans to weigh up competing claims on resources. In that case the concept of objective values outside the valuations made by humans can have no place." We have an argument along the lines of:

(P1) If only humans can weigh competing claims, then values are not independent of human judgement.
(P2) Only humans can weigh competing claims.
(C) Values are not independent of human judgement.

Again, this objection just silly. First, compare babies and the severely mentally retarded. Just as there are conflicts of interest between humans and non-human nature, there are conflicts of interest between rational humans and nonrational humans. Most people hold that babies and severely mentally retarded have intrinsic moral value; an objectivist would, of course, hold that this value is objective. Is it an argument against the objective moral value of nonrational humans to point out that only rational humans can weigh up competing claims? This is just a non-sequitur. Clearly, (P1) is mistaken. The reason why only humans can weigh competing claims is that humans are the only beings who have evolved the cognitive capacities to do so. In the same way, only humans can discover subatomic particles. It hardly follows from this that subatomic particles don't exist independently of human judgement.

Second, Sylvan and Bennett's claim is ethical, not metaethical. They aren't saying anything about objective values. Sylvan is Richard Routley, who as I noted isn't an objectivist. Again, B&P have confused ethical claims with metaethical claims. Similarly, while I don't know anything about Naess's metaethical views, his statement also clearly has nothing to do with objectivism.


In the last part of their paper, B&P present two arguments for the inevitability of human-centred values:

First we have this piece of sophistry: "it is inevitable that, to whatever view we subscribe about the value of nature, it will always be our human view. There is no other perspective available to us and there is no other perspective that can be adopted in our treatment of the non-human world."

We might compare the following argument: "it is inevitable that, to whatever view we subscribe about the value of women, it will always be our male view. There is no other perspective available to us and there is no other perspective that can be adopted in our treatment of women."

Perhaps this is unfair. B&P would presumably object that male humans aren't limited to a purely male view, since they can converse with female humans and come to understand their perspectives. We can't however understand the perspective of much of the nonhuman world, a fortiori because the vast majority of nonhuman things have no perspective whatsoever. But what can we conclude from this? All this tell us is that, if there are objective values, we will only ever be able to comprehend them from a human perspective. It certainly doesn't tell us that there are no objective values. What is true here of values is true of everything else: everything we will ever know is known only from a human perspective - mountains, rivers, cars, quarks, clothes. Presumably B&P wouldn't deny that any of these things objectively exist.

Second, B&P suggest that there is a tension in the environmentalist injunction, found for instance in the statements by Naess and by Sylvan & Bennett that we saw above, to treat all species equally. Equal treatment for all species requires extending rights or consideration to other species. But if all species are to be treated equally, why shouldn't humans act as other species do, in their own self-interest, and hence limit rights and consideration merely to humans? No other species cares about environmentalism. Ultimately, B&P suggest, our concern for the environment is really an example of human superiority.

There are several points to note about this argument. First, no environmentalist denies that humans are allowed to act in their own self-interest. Of course, environmentalists do deny that humans should act purely in their own self-interest, and presumably this is what B&P mean to suggest is entailed by the notion of treating all species equally. Second, do environmentalists really claim that all species should be treated equally? I suppose that's one way of reading the statements by Naess and Sylvan & Bennett, although it depends on what B&P have in mind by "equal treatment". As I recall Sylvan & Bennett's book (I can't cite any pages since I don't have it on me at the moment), they hold that different kinds of objects generate different kinds of obligations. Bear in mind also that many environmentalists will value species differently depending on their rarity, their importance to ecological processes, etc.

Third, B&P's argument is clearly seen to be sophistical if we consider again babies and the mentally retarded. Most people hold that babies and the severely mentally retarded should, in some important sense, be treated equally to adult humans. Or at any rate, we should hold them to be of equal moral value. But babies and the severely mentally retarded do not, of course, care at all about moral behaviour. They don't have any concept of moral behaviour. So if we are consider them morally equal to normal adult humans, why shouldn't normal adult humans act just like babies do, in their own self-interest? In this context, of course, the argument is easily seen to be silly.


B&P's paper is very frustrating. Many of their arguments are quite weak, not helped by the fact that they don't seem to be clear what exactly their target is. They claim to be attacking the view that the natural world has objective intrinsic value. Yet they address arguments only designed to show that the natural world has intrinsic value, which are neutral on the metaphysical status of this value.

I agree with B&P that the natural world has no objective value. In my view, there are no objective values period. Values are nothing more than human judgements (at least this is the case for moral values: presumably other animals value things in the sense that they enjoy or dislike them, but animals have no moral attitudes). This is a metaethical claim, and is entirely compatible with a robustly nonanthropocentric normative ethic. Indeed, I agree with Routley that the Last Man's behaviour is evil. When I say that the Last Man's behaviour is evil, I'm simply expressing my strong disapproval and disgust towards his behaviour.

B&P argue for an anthropocentric metaethic, and on this point we're in agreement. But anthropocentric metaethics is tangential to the concerns of environmentalism.


Beckerman, W. and Pasek, J. (2010) "In Defense of Anthropocentrism", in Keller, D. R. (ed.) Environmental Ethics: The Big Questions, Malden, Massachusetts: Wiley-Blackwell.

Sylvan, R. and Bennett, D. (1994) The Greening of Ethics, Cambridge: White Horse Press.