Environmentalism comes in many shapes and variants. There are those who emphasize concern for ecosystems, particular life forms, the diversity of species, levels of pollution, and climate patterns, among others. In general, it involves the prioritization of ‘naturalness’ over the alteration of the environment by humans. Environmentalists tend to want to conserve landscapes as they are, keep food chains intact, prefer ‘native’ to ‘invasive’ species, naturally grown rather than ‘artificial’ plants and foods, and prevent the extinction of ‘naturally’ evolved species. There are many who have no such preference for naturalness, and who may be more inclined towards the acceptance of human tinkering if it means the conservation or preservation of one or more of the issues in the environmentalist agenda.
Sophisticated defences of these positions involve the deployment of findings from advanced, and well-developed fields of study that are then mobilized in support of an environmentalist policy agenda – ecology, environmental biology, climate science, among others.
Like all perspectives, when translated into arguments about social matters, they fall under two broad categories: instrumental value, and intrinsic value positions. The former means that some aspect of the environment is worth defending because of the value that it has to us. These kinds of defences are mounted for various measures that are ultimately justified in terms of their ‘use-value’ for our purposes. Intrinsic value approaches defend environmentalist positions in terms of the inherent value that some feature of the environment has, independent of its use value.
Both types of reasoning can be used to defend interests that we would consider aesthetic, moral, economic, and prudential. For example, there are defences of the treatment of animals that argue that animals and other life forms have value simply because of their sentience. The concern here is that course of action X is worth doing because of the inherent value that these animals possess in virtue of their status as living beings. An instrumental defence of animal welfare might frame the need to prevent the extinction of the species as something integral to the survival of some other life forms, and the effects this would have on other things salient to human interests.
Another example concerns the preservation of an ecosystem. It could be argued that ‘natural’ ecosystems should be preserved because they are inherently beautiful, and pristine. On the contrary, they could be instrumentally defended on the grounds that ecological complexity and biodiversity are vital to preserve as they can be studied and exploited to develop life saving pharmaceuticals. It is thus the way in which the issue is ultimately framed that makes the argument instrumental, or intrinsic.
Philosophically, the choice over instrumental/intrinsic reasoning about values is a question that is rooted in an understanding of what it is about something that is the source of its value. It is an issue that has reappeared in many different domains over time, and a phenomenon that everyone should recognize in various aspects of their own lives. Is something valuable because of its use to us, or is it in some sense valuable ‘independent’ of our preferences?
If, on the one hand, you claim that a thing’s worth is ‘merely’ instrumentally valuable, then this seems to deprive it of some of its importance. It can have the sense of reducing ethics and valuation to the interests of people, and thus miss the core of what such practices are about, namely, disinterested behaviour – acting and valuing simply because something is good, or because it is beautiful. On the other hand, it seems to make little sense to say that something can have value completely independent of our own frame of reference. Can we really think that something would have any value if there were no humans around to value it? It is not a question that really makes sense, because our own frame of reference is literally all that we have to understand everything in our world. Does it not follow that any interests then must be weighed and traded off against our many other interests?
There are ‘benefits’ of framing an issue in either way. The intrinsic value type of defence can give a great deal of weight to a particular concern. If one is able to assign something inherent/intrinsic value, then this can be used as a ‘trump’ that overrides other concerns in cases of conflict. This is what some human rights advocates have done – by claiming that more and more things are ‘rights’, they hope to mobilize support and divert resources from other uses to the fulfillment of the ‘right’ of their choosing. The strong sense of importance attached to intrinsic-value-reasoning can garner a great deal of support for a cause.
Instrumental value, on the other hand, is able to identify the salient characteristics of some issue, and cast them in terms of human interests. This then allows it to be ranked and prioritized, weighed and traded off against other concerns. It is thus less emotionally appealing for some, and much more sensible to others.
There is a clear sense in which we value things strongly, and absolutely, to the point where other considerations cannot take precedence. Yet, it is equally true that – at least from the perspective of social matters, and of decision-making that affects many people – there are many competing values and concerns that cannot be met simultaneously. Furthermore, many of these values exist in negative or zero-sum relationships with each other, where the pursuit of one is in conflict with, or negatively detracts from the achievement of another.
I think that both positions – instrumental and intrinsic approaches to valuing – can be defended philosophically when conceptualized in the right way. Life is indeed sacred, and killing absolutely wrong (i.e., intrinsically, absolutely valuable). Yet, we have intuitions, arguments and a legal system that make clear distinctions on the basis of context and difference. For example, we sense that it is wrong to engage in war, but that it is sometimes justified. We tend to think that vehicular homicide demands pardon in some cases, but that some acts are so heinous that the murderers life is not worth defending. Our legal system clearly makes distinctions between types of killing – first, second, and third degree – and there are exceptions to every rule, both moral and legal.
My own take on this is that many things have intrinsic value as a rule or as a default. Nevertheless, there are degrees of difference within each thing or concept that is valued intrinsically in this way – circumstances pertaining to abortion, and types of killing, for example. This nuance, and the conflicts of value that result when strong values collide, leads us to the normative practice of making exceptions to our intrinsically valued beliefs all the time. This means that we can still conceive of some practices, and courses of action as wrong, immoral, unfortunate and so on, while still maintaining that they are the right things to do in the appropriate circumstances.
We should think this way because there is no escaping the fact that there are genuine moral dilemmas, that we have finite resources, and competing interests that cannot be simultaneously met. The only thing to be done about this from the perspective of decision-makers is to be sensitive to the interaction of the many competing factors in play, and to make decisions on the basis of a wise, compassionate, and prudential consideration of the most salient ones.
From the perspective of politics, philosophy, and personal morality alike – environmentalist concerns have their place in our lives alongside many others. Crucially, they do not form the basis, or crux of a philosophy of life or worldview. When they are elevated to this status, strange practices follow, such as those exhibited by some of the more extreme environmentalist academics, lay people, and NGOs who exhibit fanatical commitment to causes that just have their place among many others.
 For an excellent survey of arguments for and against biodiversity and environmentalism more broadly, see this excellent work on the topic. Jonathan A. Newman, Gary E. Varner, and Stefan Paul Linquist, Defending Biodiversity: Environmental Science and Ethics (Cambridge, United Kingdom : New York, NY: Cambridge University Press, 2017).