Thales and the Origin of Theoretical Reasoning

“The achievement of Thales,” notes W. K. C. Guthrie, “has been represented by historians in two entirely different lights: on the one hand, as a marvelous anticipation of modern scientific thinking, and on the other as nothing but a transparent rationalization of a myth.” According to Guthrie himself, one may say that “ideas of Thales and other Milesians created a bridge between the two worlds—the world of myth and the world of the mind.” ²

I believe, however, that the true achievement of Thales was in the adoption of intellectual procedure, which forms the basis of all theoretical knowledge.

Thales’ Water Thesis

Problem

There is a widespread belief that philosophy starts with Thales’ assertion that water is the origin of all things. Many assume that there is a connection between Thales’ thesis and the beginning of science. Having read through the extensive literature on the subject, however, I cannot find a satisfactory answer to the question of what exactly makes this thesis of Thales so important and what brought it to life. Apparently, some other scholars have a similar feeling, and therefore they tend to minimize Thales’ innovation and consider his thesis about water as merely one of a long array of traditional cosmogonies. Today, the prevailing view is that Thales only presented in his own words what the Egyptians or Babylonians had said previously.³

The question of the Middle Eastern origin of Thales’ thesis is not, of course, as important as the status of his starting-point: is it an assertion about what was first in the world (as it is presented in traditional cosmogonies), or was it also an assertion about the basic element or stuff that is a constituent element of all things? (If the latter, then a fundamental difference from Middle Eastern cosmogonies is obvious.) ⁴

The latter interpretation, which goes back to Aristotle and Theophrastus, was the prevailing one until the middle of this century, shared by the majority of scholars who wrote about Thales, the Milesians, and the birth of philosophy and science. What, then, did those authors say about (a) the motives that made Thales advance the thesis, and (b) the historical significance of this thesis?

The most typical is the following. We are told that Thales and the Milesians proceeded from the assumption of a fundamental unity of all material things that is to be found behind their apparent diversity. So the task of these philosophers was to establish what exactly provided this unity: one said it was water; another, the Boundless; yet another, air. They arrived at this presumption of unity beyond diversity partly through a certain intuition, partly under the influence of some impressions obtained from experience. Yet interpretations of this sort suggest no explanation of how the idea of the unity of all material things could have become a presumption, a reference point for investigation and discussion for the first philosophers, whose everyday experience unambiguously indicated that the different material things around us are not alike-some are derived from things of one sort, and others from things of quite other sorts.

Let us consider some concrete proposals. John Burnet has suggested that the opposition of day and night, the changes of the seasons, and so forth brought the first philosophers to an idea about the critical importance of the interplay of opposites in the world around us. “That, however, was not enough. The earliest cosmologists could find no satisfaction in the view of the world as a perpetual contest between opposites. They felt that these must somehow have a common ground, from which they had issued and to which they must return once more.” ⁵ Yet Burnet does not explain how one can “feel” that everything consists of one stuff (be it water, air, or something else) in a world filled with contrasts such as the change of day and night.

According to Theodor Gomperz, Thales’ thesis could have been stimulated by observations of plants obtaining nutrition from soil, air, and water to become, in turn, food for animals, as well as by observations of the decay of living...