Although it is easy to form a general idea of nature and the natural, it is difficult to define nature precisely and to differentiate things and processes that are natural from those that are not. A first approach to such a definition is to conceive the world of nature as what is experienced when a person goes into a primeval forest or gazes out on a starry night into the depths of space. The natural in such experiences is perceived as what is free from human intervention and artifice, what comes into being and runs its course without benefit of...

To speak of the inanimate world is to presume that there is a difference between the living and the nonliving and that this difference is easily recognized. Now admittedly there are natural entities whose kind is difficult to establish and which thus might leave us in doubt whether life can be predicated of them. But most specimens encountered in normal surroundings do not present this difficulty: we classify them as plant or animal if they manifest vital activities at one level or another, and if not, we regard them as inorganic. Ores and minerals fall in the latter category; they...

Unlike the inanimate world, the world of plants and animals offers a rich abundance of natural kinds that have been recognized as such for millenia. Students of nature have not been content merely to distinguish the living from the nonliving or plants from animals. but have worked seriously at differentiating each type from every other. In this project the sense of “natural kind” is that it designates a class of things alike in all their essential characteristics, that is, sharing a common nature though differing in individual traits.

The abundance of detail available in the study of organisms makes it...

Our discussion of animal natures in the preceding chapter has concentrated to a large extent on the powers they have in common with plant natures. The distinguishing features of organisms within the animal kingdom, as has been noted, are their sentience and mobility, but apart from identifying the powers from which these activities originate, we have offered little by way of explanation of them. In this chapter we propose to remedy this deficiency by elaborating on these features. and particularly on sentience, for this is inextricably tied to animal movements of various types.

By sentience we mean simply sense knowledge...

Human life is very different from other forms of life found in the universe. In this chapter we shall address the questions of what it means to be a human being and what there is about homo sapiens that sets him apart from all other creatures. Why is it that when we juxtapose the terms “nature” and “human nature,” we have the feeling that these terms refer to entities that have little in common? The answer is surely to be found in some eminent characteristic that differentiates the human from the nonhuman, or, to phrase this in language that is...

The first part of this volume has focused on the concept of nature. Using that concept it has ranged over areas of investigation that pertain to all the natural and human sciences, and thus it can rightfully lay claim to being a philosophy of nature. The question that arises from this claim is whether or not the philosophy thus elaborated may also be termed a philosophy of science. A negative answer to this question might be suggested by the fact that nature and science are two different things: nature is an enduring extramental reality. something that exists in a mind-independent...

Of the tasks set out at the end of the previous chapter, the easiest is that of explaining the dialectical character of modern science, that is, why it typically is not able to achieve demonstrative or apodictic knowledge but must settle for conclusions to which assent is given only with greater or less probability. This aspect of science has been fully explored within the logical empiricist tradition, and thus a recapitulation of some of the findings of that tradition will provide the essential elements on which the probabilist view rests.

As its name suggests, logical empiricism makes heavy use of...

The current state of the philosophy of science as portrayed in the last two chapters would seem to indicate that somewhere along the line the magnificent enterprise that was fathered by Galileo at the beginning of the seventeenth century has gotten off the track. Precisely what derailed it is not agreed upon among scholars. Apart from those of the twentieth century, the philosophers who have been most studied are David Hume and Immanuel Kant. Both turn out to be unfortunate choices in matters epistemological, the first for his skepticism with regard to a science of nature, the second for his...

The discussion to this point has focused on an idealized view of science’s epistemic dimension, simply presenting the requirements that have to be fulfilled if one is to be certain of one’s conclusions and perhaps suggesting, albeit unintentionally, that these requirements are easily met in the investigation of a particular subject matter. Nothing, of course, could be farther from the case. Demonstrative knowledge represents the summit of scientific knowledge and, as the history of science reveals with its unending account of revisions and theory changes, it is not readily attained. The main problem being addressed in this volume is, in...

Most of the conceptual studies presented in the previous chapter contained proofs that when formulated were regarded as demonstrations or as apodictic arguments, and yet not one, with the exception of the last, was immediately accepted by those to whom it was proposed. Is this an anomalous situation, or is it something that is to be expected in matters pertaining to science’s epistemic dimension? Aristotle wrote the Posterior Analytics with the idea in mind that it might provide canons that would prove useful “in teaching and learning through discourse” (71a1), meaning by discourse (Gr. διανοητικός) the use of a reasoning...