The Electronic Journal of Analytic Philosophy is a forum for discussions at the cutting edge of philosophical research. Environmental ethics is part of this cutting edge. The first major conference of this young discipline, with the theme "philosophy and environmental crisis," was held at the University of Georgia in 1970. Since then, increasing numbers of moral philosophers have begun wrestling with the problem of the environmental crisis.
 It is obvious that the environmental crisis involves political, social, and economic aspects. What is less obvious is that it also poses a philosophical problem. In a nutshell, the problem is this: clearly, something is deeply wrong with the continued destruction of nature. Clearly, the environmental degradation is a destruction of some good, a destruction of something with a positive value. But the available ethical tools for explicating notions of wrongness, good, and value have traditionally been limited in their application to the human domain. We do not know yet how to put the wrongness of damages done to nature into satisfactory theoretical form -- something with a positive value is harmed by environmental degradation, but the actual character of this value must still be specified.
 At the very least, what is destroyed by environmental degradation possesses an instrumental value for human interests. Since we depend to some extent on the integrity of the biosphere, and since we enjoy, again to some extent, the same integrity, the destruction of the biosphere does not serve our interests. Considering this, environmental degradation is undesirable. But by proceeding from the sole basis of human interests, we can show the undesirability of environmental degradation only to an extent; we cannot show it to be undesirable in general.
 Appeals to human survival do not suffice to justify ecological integrity, given the remarkable human ability to adapt to altered environments -- humans could live, and live comfortably, in a world that contains tree farms instead of forests, lawns instead of meadows, fields instead of wetlands, and so forth, as long as such a changed landscape remains tolerably unpolluted. Nor do appeals to human happiness suffice; the existence of pristine stretches of wilderness is not a necessary condition for human well-being as such. Human well-being can even be served by the eradication of wilderness: by operating solely with human needs, it is hard to argue for the preservation of a mosquito-infested swamp which could be turned into a public park or a housing development if it were drained.
 Mere human interests do not point to the general ethical desirability of environmental integrity. This does not mean that this desirability cannot be demonstrated in principle. Nor does it mean that environmental ethics revolves around an arbitrary assumption that we ought to preserve nature, making the whole endeavor into a fruitless exercise of normative circularity. The fundamental assumptions of this endeavor are rather these: first, we should extend our moral concern at the very least to anyone who has an interest in, or desire for, his or her well-being. And second: humans are not the only entities possessing such interests, preferences, or desires; higher developed animals such as mammals and birds are endowed with them as well, and thus qualify as moral patients just as humans do. The first assumption is a basic premise of all ethics. The second assumption is a basic premise of environmental ethics.
 To deny the first assumption means to deny a moral concern for beings interested in their well-being. Such a denial would result in ethical nihilism at best, and in the condoning of genocide, racism, etc., at worst. Let us therefore accept the first assumption. But why should we accept the second assumption -- why should we care about the interests, preferences, desires of nonhuman beings? There is a logical reason for this. Suppose a sceptic grants the basic premise of ethics, of extending moral concern to beings interested in their well-being. If the sceptic subsequently denies a similar concern for nonhuman beings, on the sole basis that they are nonhuman, then the sceptic will draw a boundary divorcing sentient human beings from sentient nonhuman beings. This boundary is not rationally defensible. If both human and nonhuman beings desire their own well-being and have a capacity for experiencing pain, then both kinds of beings can be benefited and harmed in an equally literal and non-metaphorical way. Hence, both kinds of beings qualify as moral patients. To acknowledge the one kind but not the other as falling into the category of a moral patient is inconsistent.
 If, however, the sceptic denies a moral concern for nonhuman beings because, in the sceptic's view, they are not sentient, hence do not possess any morally relevant interests, desires, or preferences, then the sceptic will embrace a conception of nonhuman beings that is not rationally defensible either. Animals such as mammals and birds are then reduced to silly caricatures, to Cartesian machines or Skinnerian behavior-systems. Appealing in good old analytic fashion to the inaccessibility of internal mental states, hence to the inaccessibility of subjective pain-experiences, does not help the sceptic's cause. We know about the mammalian and avian capacity of experiencing pain in the same way as we know about this capacity in other human beings besides ourselves. Other humans can suffer. So can animals. As soon as we accept the former, we will be committed to accepting the latter. It is therefore more reasonable to accept the basic premise of environmental ethics than to reject it, namely, that other beings besides ourselves are sentient and qualify as moral patients.
 As a result, we can measure the desirability of nature's integrity both in terms of nature's instrumental value for humans and in terms of its instrumental value for nonhuman sentient beings. Now, a minimum conception of environmental ethics can be constructed: given that mammals and birds have interests in their well-being that are morally relevant, given that the degree of their well-being depends on the degree of integrity of the ecological niches they occupy, and given that practically any wilderness on earth comprises habitats for mammals and birds, it follows that the existence of pristine stretches of wilderness has a positive instrumental value that is morally relevant. In other words, environmental integrity in general can be shown to be ethically desirable.
 If we accept this inference, then nature will be endowed with some value. This value, furthermore, is sufficient to construct a normative system of environmental ethics. But is this all? Is nature's good limited to an instrumental value for sentient beings? Is there perhaps more to it? If so, then nature would seem to possess, in addition to its instrumental value, an independent intrinsic value. Can this be determined? Can we justify an intrinsic value of nature?
 One might argue that such questions are superfluous. Since environmental ethics appears to be viable without these additional constructions, why, then, should we bother with the metaphysical ins and outs of intrinsic value? After all, a good theory should be parsimonious, as lean and mean as possible, and if the aforementioned pair of basic assumptions succeeds in doing the normative job we expect environmental ethics to do, then this ought to be enough. Environmental ethics as an efficient practical casuistry may well dispense with supplementary axiological inquiries, or so it seems.
 Yet, the endeavor of environmental ethics remains fundamentally incomplete without the clarification of intrinsic value. After all, the initial philosophical problem sparked by the environmental crisis concerns this question directly: something is wrong with the destruction of nature, something valuable is destroyed; how can we make theoretical sense of the value apparently contained in nature? Hence, the question of nature's value is not peripheral or supplementary to the task of environmental ethics. It lies at the very heart of the philosophical endeavor.
 The difficulty of this question can be highlighted by two opposing and equally persuasive lines of thought. Consider first the case against intrinsic value in nature: we judge mammals and birds to be morally valuable (that is, deserving of moral concern) because of their factual features. Clearly, we assess certain factual properties which characterize sentient beings as being valuable, such as their desires for well-being or their capacity of experiencing pain. Likewise, we may be willing to invite nonhuman and nonsentient parts of nature into the domain of moral concern because we assess these parts of nature valuable on other grounds. For example, we judge the factual properties of rainforests or of coral reefs as being valuable, namely their ecological complexity, their organic richness, their systemic coherence, and so forth. No matter how we slice it, though, it is always we who do the valuing.
 In the last analysis, therefore, Hume's description still seems to appy: value judgments are mere sentiments of approbation and disapprobation arising in our own breasts. Values come from us, and we attach them to the facts. Facts are out there. Values are not, so it seems. Since we impose values on facts through our judgment, it apparently follows that values are always extrinsic to the properties of subject-independent objects. An "intrinsic value," in this light, is as much of a contradiction in terms as a square circle. This is the case against intrinsic value.
 Now consider a possible case for intrinsic value in nature: Our valuing, if well-grounded, may be a sufficient condition for the value of an object, but it is not a necessary condition for the value of an object. The presence of a value does not presuppose the presence of us as valuers. Certainly, we can evaluate mammalian and avian desires for well-being in a positive way. Regardless of our evaluation, however, the animals in question already value their own well-being. It is human prejudice to believe that only conceptualized values can be values. Given that nonhuman sentient beings demonstrate through their behavior that they have preferences for their well-being, given that such preferences illustrate that their well-being is a desirable state, it follows that the well-being of nonhuman sentient beings is valuable for these very beings. Considering this, the value is already out there; it is already attached to the facts -- regardless of whether or not we humans impose, in addition, our own informed value-judgment on these matters.
 Now we can draw some inferences. Since these nonhuman sentient beings themselves attach a positive value to their own well-being, their well-being is neither a fact that is value-neutral, nor is it a fact whose possible value is contingent on mutable preferences. Instead, well-being is fundamentally desirable for sentient beings. Hence, well-being possesses a value that is an essential component of the sentient beings' life. As an essential component of sentient life, the value is intrinsic to the fact of well-being. Now, since these nonhuman sentient beings are integral elements of ecosystems, they are genuine parts of nature. Therefore, nature contains intrinsic value through the desired goal-states of its sentient members.
 We can even go a step further. The case for intrinsic value in nature could be pushed beyond sentients. As it is human prejudice to reduce value to conceptualized value, it may be sentient prejudice to reduce value to felt value. Clearly, ecosystems such as rainforests possess goal-states. If a rainforest suffers some limited damage, the rainforest will regenerate. Its growth is always directed towards attaining a particular equilibrium between a maximum diversity of species and a maximum quantity of biomass. This equilibrium is the rainforest's ecological integrity.
 Consider now the following inferences: since ecological integrity is the goal-state that characterizes the flourishing of a particular ecosystem, ecological integrity is intrinsically valuable for the ecosystem. As the essential objective of collective growth, this integrity possesses a positive value within the ecosystem, regardless of what we humans think, regardless of whether or not we pass an additional positive value judgment. Therefore, nature contains intrinsic value through the very integrity of its ecosystemic components. This would be a possible case for intrinsic value.
 The question of nature's intrinsic value is the core of the philosophical problem of the environmental crisis. It is a difficult and puzzling question, because there are arguments on either side of the fence that are not easy to refute. In the last ten years, the interest in this question has grown steadily, from the first explorations in Paul Taylor's Respect for Nature in 1986, to the forum on the intrinsic value of nature in The Monist in 1992, to a host of new publications since then. The final judgment on this matter is still out. But the contributions to this issue of The Electronic Journal of Analytic Philosophy, by some of the leading and most renowned thinkers in the field, will bring us closer to the answer.