Understanding how we should think about ourselves as humans constitutes a problem with a long and complex history. The history is long because this problem is at the heart of the Western philosophical tradition. Moreover, arguably any ancient religious and cosmological tradition is effectively founded on a theory of human nature. The history is intricate and complex because, as a cursory look at the literature in philosophical anthropology can show, defining human nature is not a straightforward endeavor. This could possibly show just an implicit conceptual limit with definitions in general: it turns out to be surprisingly difficult to establish the necessary and sufficient conditions for determining what it means to be human. However, the problem with the concept of human nature is much deeper. Indeed, there is a strong suspicion that human nature is just a dispensable concept, legacy of a pre-scientific age. This would imply that philosophical anthropology is a discipline devoid of subject matter. This widespread scepticism is nowadays mainly motivated by the acceptance of an evolutionary argument. The challenge of editing a book on this topic is therefore to show that human nature remains a significant philosophical concept. Is the book successful? The book has one easily recognisable limitation: the preface is far too short, being therefore unable to provide the background necessary to guide the reader. Without this interpretive context the contributions seem to be too loosely connected. I suggest that one way to evaluate the book as a whole is to consider whether its contributors manage to defend the philosophical legitimacy of the notion of human nature, especially in the light of the scepticism generated by the evolutionary argument. Let us thus take a look at the evolutionary argument.

For any possible group of objects it could be asked, for instance, whether there exist properties that are universally distributed (i.e. shared by all the members of the group) and peculiar (i.e. distinctive only of the members of the group). For instance, it is difficult to imagine a television without screen. Indeed, screen-free televisions might not yet exist, or might not possibly exist. Establishing the latter point would make having a screen an essential feature of televisions. It was also difficult to imagine mobile phones without keys until key-less phones were invented. This means that having keys is not an essential feature of mobile phones, or, put it differently, the property of having keys does not belong to the essential nature of being a mobile phone. I have so far applied the essentialist argument to artifacts. Let us now consider if it can be extended to natural entities. Surely, one might think, all pieces of gold have some essential feature, some universally distributed and distinctive property that necessarily defines all items of the substance. Similarly, one might think that all atoms, magnetic fields, organic molecules etc. could equally possess essential features. Let us now suppose that artefacts and non-living natural entities possess essential natures. Switching our attention to living things, the intuition that this subset of natural entities can be defined in essentialist terms has received an unprecedented challenge with the advent of evolutionism. In fact, if species evolve in the course of time, then one essence could be transformed into a different one. After all, the evolutionary story states that unicellular organisms transmutated into humans. Thus, the supposedly essential property universally distributed among the members of the original species and distinguishing it from other living forms might mutate or even disappear. Essential natures, from the perspective of evolutionism, are not static. Evolutionism therefore implies that human nature, as conceived by Aristotle or Descartes, does not exist. Darwin himself suggested that there is no fundamental difference between humans and animals, that the cognitive, ethical or even ontological fracture assumed to exist between us and the rest of the natural world is spurious. So, with the advent of evolutionism transmutation became a fact that needed to be scientifically acknowledged, first in biology, then in the sciences of human nature, and eventually even in the physical sciences. There are strong reasons to believe that even chemical elements transmutate, and that indeed the physical universe, the cosmos, must be understood in evolutionary terms. If this is indeed the case, if all sciences are ultimately evolutionary sciences, and if evolutionary issues are the most fundamental ones, then it turns out that no natural entities can be defined essentialistically.

So, focusing on the human sciences, what are the implications of accepting the evolutionary argument? All the human and biomedical sciences are based on an implicit notion of human nature. Many of the pronouncements of, for instance, immunologists, pathologists, psychologists and economists would not make sense otherwise. Possibly human scientists use a different concept of human nature that is not essentialist. But, if this is indeed the case, we might desire to know what sort of concept we are dealing with. Evolutionism might imply that human nature cannot be defined essentialistically, but is there any non-essentialistic alternative to think about humanity? Furthermore, does evolutionary biology really show that there is no such thing as human nature? Or does this simply mean that evolutionary biology has nothing interesting to say about humans? These are the basic questions spurred by adopting the evolutionary perspective that form the background of many of the contributions in this book. Does the book answer these questions? It certainly contains some interesting contributions. One author suggests that there is a concept of human nature that is not essentialistic and that is sufficiently profound in order to make sense of the claims of the human sciences. Another suggests that it is a limit of the neo-Darwinian interpretation of evolutionary theory what generates the tension between evolutionism and essentialism. Partially following the same line of reasoning, a third author suggests that the tension between evolutionism and essentialism is not genuine because, as a matter of fact, evolutionary theory is not only compatible but presupposes an essentialist metaphysics. These authors make a serious effort to resolve the philosophical impasse generated by evolutionism while at the same time trying to make sense of scientific practice. But, despite these contributions, overall the book is deficient. One problem is that the editors do not inform the reader as to what their philosophical aim is. As a consequence, and even assuming the interpretive bias I have been using in this review, the book as a whole remains fragmentary. The second problem concerns the choice of contributors, all philosophers except one biologist with a strong interest in psychiatry. There is nothing wrong in presuming that philosophers have something to say on a traditionally philosophical topic, but, given the multi-disciplinarity of the study of human nature, one would expect a more varied range of perspectives.

© 2013 Davide Vecchi

Davide Vecchi did his Ph.D. in philosophy of science at the London School of Economics. He has been Research Fellow at the KLI for Evolution and Cognition Research. He is now lecturing at the department of philosophy of the Universidad de Santiago de Chile. His main research interests lie at the interface between biology and philosophy.