HUMAN NATURE AND THE NATURE OF SCIENCE I
The account of science presented in Chapter 3 meets with an objection: my notion of a fundamental practicality of science goes against the grain of traditional philosophy of science. Philosophers have observed that scientific theories are seldom accepted or rejected on the basis of their practicality. They have also observed that scientists are more likely to be motivated by the search for truth or the satisfaction of their intellectual curiosity than by the good of mankind. This tradition is eloquently expressed in the words of another great French scientist and philosopher, Henri Poincare, who at the beginning of this century wrote that "the scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful. If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living." 
For Poincare the beauty that really counted was not that of "qualities and appearances" ‑‑ the beauty accessible to most human beings ‑‑ but rather that "profounder beauty which comes from the harmonious order of the parts, and which a pure intelligence can grasp." That sentiment is not surprising in one who dedicated his life to understanding nature. But not all humans are so dedicated, and some of them have interests that would not coincide in the slightest with those of a mathematical physicist like Poincare. Nevertheless I think that Poincare was right in saying that scientists seldom study nature because it is useful. But I would stress a consequence, perhaps unintended, of his argument: that because life is worth living, nature is worth knowing.
The reason is that there is a sense in which the satisfaction of scientific curiosity has something akin to adaptive value. To see this more clearly it is helpful to consider how the nature of science arises from the nature of man. And by the nature of man I have in mind that human beings are biological products of their universe, as much a part of that universe as trees and stars. Let me begin, then, by pointing out that curiosity has adaptive value in animals. Of course not all animals have curiosity, but those that do, say the Norway rat or the raven, can adapt to a great variety of environments or to a changing environment. Curiosity, most often in the spirit of play leads them to obtain knowledge of the environment in which they find themselves. Curiosity is thus the key to their flexibility ("specialists in non‑specialization," Konrad Lorenz called them), and their flexibility is the key to their adaptive success. We must also remember that the structures that underlie intelligence are biological. As a result, Jean Piaget says that intelligence "...is the most highly developed form of mental adaptation, that is to say, the indispensable instrument for interaction between the subject and the universe when the scope of this interaction goes beyond immediate and momentary contacts to achieve far‑ reaching and stable relations."
In short, intelligence has adaptive value. But science is not only a product of intelligence: it is also a means by which intelligence conceives of the universe, as we have seen. In such a case, should not science be expected to have adaptive value as well? Many of the lines of argument developed in this chapter should testify in favor of this claim (e.g. the relation between theoretical achievement and realization of opportunity or of danger). It must be kept in mind, however, that not all our faculties were selected for their present uses. But there is no suggestion here that human brains were selected for atomic physics or to build space telescopes. The selective forces had long done their job before humans thought of atoms or rockets. Nonetheless this consideration does not prevent a faculty developed for something else to acquire adaptive value of its own. And in the case of science the connection is even closer than that, as I will discuss next time.