Aristotle on Circular Motion

In this book, Jean De Groot (hereafter D) engages in a single-minded defence of a particular thesis about Aristotle's empiricism. Instead of focusing on his study of animals (D is not as sensitive as some would now be to anachronism of calling this his biology), she concentrates on use of notions, especially what she dubs radius principle. This expresses idea that speeds with which points on a circumference move vary directly with length of radius of circle in question, where she correctly notes that it was more awkward to speak about this in fourth-century B.C.E. Greek since there was no single term for radius, only various locutions such as the [straight] line drawn from centre. One surprising feature of her discussion is that although moving radius principle applies to any circular motion, she sometimes speaks of it as one of movements into which, in concentric spheres models of Eudoxus, Callippus, and Aristotle, planetary motion is resolved.The book maintains that - despite some recent studies of which I would rate Sylvia Berryman's 2009 monograph, The Mechanical Hypothesis in Ancient Greek Philosophy , most important - notions have been unjustly neglected both by Aristotelian scholars and by historians of Greek science, although D is careful to distinguish ancient Greek views from those associated with mechanical of seventeenth century. In process, D attacks some views that are, to be sure, grossly exaggerated, straw men in other words. One is idea that Aristotle read physical principles off surface of things (p. 15), and a second, view that would reduce his of to a philosophy of common opinions about nature (p. 15), i.e., that it is dialectic or endoxic in character, rather than adopting a scientific attitude to subject, that is one that we can recognise as such.For this enterprise, D draws heavily on Problemata and Mechanica , works generally thought not to be by Aristotle himself but probably emanating from his circle. This is a legitimate procedure, she claims, for two main reasons. First, there is enough evidence in admittedly genuine works (e.g. On Generation of Animals II 1 and 5, and Movement of Animals 1 and 7) for Aristotle's interest in ideas, so we should be allowed to supplement this with material from more doubtfully authentic works. Second, even works accepted as Aristotle's own are, as far as we know, notes of his lectures written by his students, or by Aristotle himself and then rewritten or reorganized by others (p. …