Exploring the Value of Species

The extinction of species is generally regarded as a bad thing. We campaign to save the whales, protect the pandas and so on. In my project, I considered these assumptions, whether they can be justified, and what this might mean for conservation debates. The first major question to answer was one I didn’t expect to find great difficulty with: if we are concerned with the death of species, what is a species? Prior to beginning my research, this seemed like an important question, but not one that would be terribly hard to tackle. Biologists surely had a thorough species definition. In fact, defining species is a contentious issue, at the center of many debates within the Philosophy of Biology. It became apparent at the beginning of my project that this issue would become a sizeable portion of my work in this internship.


Many people are familiar with the folk-definition of species; two animals are members of the same species if they can produce fertile offspring. (What we mean to say, of course, is two animals are part of the same species if their respective populations can, in general, produce fertile offspring.) This way of defining species is, however, hugely problematic. For one thing, many species – indeed, the majority of the species on earth – do not reproduce sexually, so the definition is meaningless. Even for sexually reproducing species, this account fails to draw the lines we would want to. Most notably, we have cases of ‘ring species’, a collection of species such that the first may breed with the second, which may breed with the third on so on. However, the final species may not breed with the first. This would mean “is the same species as” is intransitive: we may have that A is the same species as B and B is the same species as C, yet A and C are different species. Clearly, this is unacceptable.


It became clear, having delved into the literature on this topic, that most accounts of species fall into one of two approaches: they emphasize either the similarities between the members of a species or the relations between them. We must consider whether two organisms are members of the same species because they are alike, or because they have shared ancestry. Any answer to this question is plagued by problems, but emphasizing similarity has particular shortfalls in the context of projects such as mine, in that it undermines much of the meaning of extinction. Extinction is generally understood to be the end of a species, it’s death. However, if species are united by similarity, then it seems species behave like classes, rather than individuals. Chemical elements are an example of classes: an atom is ‘gold’ if it has the requisite structure. Gold cannot go extinct. True, every instance of gold could, conceivably, cease to exist. But if an atom appears later with the requisite atomic structure, then this atom is Gold. The intervening period with no gold atoms is not relevant. If species behave like this, then extinction is not a permanent event; the elephants going extinct simply means “there is nothing currently alive that is like an elephant”. Equally, if the elephants were to go extinct but millennia later hippos had evolved to a point where their descendants were indistinguishable from elephants, we would have to conclude that the elephants were back. For these reasons, I adopted the approach that species are not groups defined by likeness, but lineages.

A crude Cladogram of the “tree of life” mapping the development of the kingdoms.

I was then able to turn to what had been my main question initially; if species extinctions are bad, how should we understand this value? The way species value is typically understood, it is not a value we can ‘maximise’. In general, we would think if a thing is good then more is better, but some values create odd implications if we claim this. This idea can create many issues when we consider species value. Suppose we are very concerned about the prospect of the white rhinos going extinct. If it is the valuable things individual white rhinos themselves, then perhaps we wish to maximise the number of white rhinos. However, this would remain true long after they are saved from extinction; even once white rhinos had reached a large, stable population size, we would still want more of them. Perhaps we should set up white rhino colonies in the western isles and America, just to make sure there as many possible. The same would be true for any other animal’s extinction we are concerned with. This is plainly absurd. Suppose instead, we are concerned with the total number of species; again, the more the better. This does give us reason to be concerned with extinctions, but not with the overall number of the members of the species. So far, so good. But it also suggests a symmetry between prevent species extinctions and developing new species. If I’m faced with the choice between saving one species or creating three new species using genetic engineering then I should choose the latter. Yet, this does not seem to track most people’s intuitions. The kind of problems reappeared throughout the project; finding a solution to one problem, only to find it’s conclusions were more bizarre than the problem it was solving. Ultimately, I managed to construct a thesis which, I believe, manages to capture the common intuitions about extinction, without succumbing to common unappealing conclusions. I also considered what these theses mean for the recent debate surrounding whether we ought to ‘bring back’ extinct species via de-extinct species and, indeed, whether we can.


In addition to what I have learned during my project about the philosophy of biology and the literature on conservation, this internship has been a valuable insight into academic research. One of the most valuable aspects of this experience was seeing how – despite feeling I had a clear idea of my project and theory at the outset – elements of the project which seemed unimportant at first swell to become large portions of the final product. Equally, parts I was sure would be significant often became almost trivial. In completing this project, and especially through discussing my problems with other interns, it became clear that not only is this a common problem, it isn’t really a problem at all. Many elements of the project which felt at first like I was failing were, in fact, natural parts of the research process. There are certainly things I would do slightly differently next time. However, had I known the complete structure of my final output at the start of the project, the project would have been pointless to complete. Likewise, it was often disheartening when threads turned out to be dead ends – but had I not taken the time to consider these threads, I would not know they were dead ends, and my work would not have been thorough. To realise that many of the things that I viewed as failures were just necessary parts of the process has been incredibly valuable. Overall, completing the Laidlaw internship has confirmed that I definitely wish to pursue research as a career path.