The nature of the differences and similarities between man and animals is one of the oldest controversies in the history of Western intellectual thought. From Aristotle to Hume, it was a central philosophical problem. The peak of activity was reached from the sixteenth to the eighteenth century ending, as a philosophical issue, with the work of Hume. In the present view, support for a naturalistic interpretation is provided principally through the influence of Montaigne, Bayle, and Hume, sustaining an interpretation so fundamental to the thought of today. Do animals reason? Until Hume, there was essentially little interest in the problem per se. The controversy was based on the philosophical and theological implications of the question. But even within that context, Montaigne, and then Bayle, were the first to state the logical nature of the argument. And, finally, with Hume, the topic was considered for itself. Given the behavior of man and animals what can one infer from that behavior? And the answer is that originally given by Montaigne: from like effects we can reasonably infer like causes. This same logical concept is at the heart of modern Behaviorism. But the major break with the past concerns what may be inferred. To Watson, of course, no inferences about conscious states, either in man or animals, are legitimate. No such notion appears anywhere in the previous two thousand years of discussion. Thus, while Hume and Watson might have agreed on the logical foundations of effect and inference in this case, they represent quite different points of view on what constitutes acceptable causal conditions. It is in this difference, and not in the logical essence of theoretical development, that modern Behaviorism represents such a radical departure from previous theory.
The Developmental Acquisition of Motion