3—
The Problem of Induction and the Atomistic Postulate

One can say much more here, however. Indeed, one can put the entire concept of induction in a sharper historical relief.

The concept of induction goes back to Aristotle's idea of epagoge .^[9] Indeed, the Latin term inductio was first introduced as a translation of epagoge . It is far from clear, however, that epagoge really is the same idea as our received concept of induction, and it will be argued below that it is not. In any case, the "problem of induction," by which everybody means the problem of justifying induction, was only thrust to the forefront of philosophical discussion almost two thousand years after Aristotle by David Hume.^[10] Why the time lag? Were pre-Humean philosophers too confused or too naive to appreciate the importance of the problem of induction? I don't think that they were. It can be shown, if I am right, that the ascendancy of "Hume's Problem" of induction is part and parcel of the same problem situation as contemporary philosophers' virtually unanimous assumption of the Atomistic Postulate. In fact, this is a natural occasion to put the entire concept of induction into an overall historical perspective.

First, it can be seen where the idea of inductive inference as an essential ingredient of the scientific process comes from. It is one possible reaction to the problem situation created by the assumption of the Atomistic Postulate. If this postulate is adopted, then a scientific theory (e.g., the initial theoretical premise T) cannot itself be derived by means of the interrogative procedure without an equally strong or stronger theoretical premise. For no nontrivial general laws can be deduced from particular propositions, for instance, from Nature's answers to questions concerning particular cases or particular situations. Hence, the suggestion goes, the two kinds of steps of the interrogative procedure, questions and deductive inferences, have to be supplemented by a third kind of step. This step is calculated to lead us from Nature's particular answers to general truths. And it is this role of generalizing steps that inductive inferences are supposed to play.

At the moment I am not discussing the intrinsic merits or demerits of this idea. What is relevant here is a simple historical prediction (or retrodiction) that can be based on my diagnosis of the rationale of the general idea of inductive inference. What follows from my analysis is that, for those philosophers and scientists who did not adopt that Atomistic Postulate, our received idea of induction was not likely to play the same role as it does for us. It was not needed as a supplement to deductive inference. There did not exist for such philosophers any Humean problem of justifying induction, for induction in our sense could largely be dispensed with. If such thinkers used the idea of induction, it was in some different kind of role altogether.

In particular, it can be expected that philosophers and methodologists who do not believe in the Atomistic Postulate will not abide by the current idea of induction as an inference from particular cases to a generalization. For, in the face of the Atomistic Postulate, it was precisely this kind of generalization that induction was supposed to mediate. If you don't accept the postulate, you don't need induction for this purpose.

Likewise, it is clear that the central role of "the problem of induction" is due to philosophers' adoption of the Atomistic Postulate.^[11] Hence this problem of "justifying induction" can be expected to occupy only those philosophers who have tacitly accepted the postulate. This observation helps in fact to explain why "Hume's Problem" became a central problem in philosophy when it did—and also how, as I will show below.

Now, as a matter of historical fact, the Atomistic Postulate was not adopted in the earlier tradition of philosophy and science from Aristotle to Newton (inclusive), though for different reasons in the case of different historical figures. In the Aristotelian tradition, even perception can give us forms, which are already by themselves general concepts. Moreover, their presence in the soul ipso facto implied according to Aristotle awareness of certain general laws, namely, those laws that specify what forms necessarily accompany the given ones.^[12] (Thinking of a certain form is for Aristotle to have it realized in one's soul. Hence what necessarily accompanies this form is also automatically present in the soul, that is, is also necessarily thought of.)

This rejection of the Atomistic Postulate by Aristotle is seen in other ways, too. Another indication is the fact, brought out by G. E. L. Owen and others, that the phainomena and endoxa which a theory was supposed to account for according to Aristotle, were not all particular facts but could include general laws.^[13]

In Newton, his reason for dispensing with the Atomistic Postulate is different. It is Newton's firm belief in the experimental method as being able to give the Inquirer general laws as answers to experimental "questions put to nature."^[14] Hence induction in our contemporary sense was not needed by Newton.

In either type of case, induction can therefore be expected to amount to

something essentially different from our post-Humean conception. A widespread failure to appreciate this historical fact has in my judgment seriously impaired philosophers' understanding of the early history of the concept of induction. I don't think that most philosophers or historians really have a realistic idea of what Aristotle or Newton meant by induction.