108 PHYSICAL SCIENCES IN ANCIENT GEEECE. 



theorized under a lively persuasion that a Science of every part of 

 nature was possible, and was a fit object for the exercise of man's best 

 faculties ; and they were speedily led to the conviction that such a 

 science must clothe its conclusions in the language of mathematics. 

 This conviction is eminently conspicuous in the writings of Plato. 

 In the Republic, in the Epinomis, and above all in the Timceus, this 

 conviction makes him return, again and again, to a discussion of the 

 laws which had been established or conjectured in his time, respecting 

 Harmonics and Optics, such as we have seen, and still more, respecting 

 Astronomy, such as we shall see in the next Book. Probably no suc- 

 ceeding step in the discovery of the Laws of Nature was of so much 

 importance as the full adoption of this pervading conviction, that there 

 must be Mathematical Laws of Nature, and that it is the business of 

 Philosophy to discover these Laws. This conviction continues, through 

 all the succeeding ages of the history of science, to be the animating 

 and supporting principle of scientific investigation and discovery. 

 And, especially in Astronomy, many of the erroneous guesses which 

 the Greeks made, contain, if not the germ, at least the vivifying life- 

 blood, of great truths, reserved for future ages. 



Moreover, the Greeks not only sought such theories of special parts 

 of nature, but a general Theory of the Universe. An essay at such a 

 theory is the Timceus of Plato ; too wide and too ambitious an attempt 

 to succeed at that time ; or, indeed, on the scale on which he unfolds 

 it, even in our time ; but a vigorous and instructive example of the 

 claim which man's Intellect feels that it may make to understand the 

 universal frame of things, and to render a reason for all that is pre- 

 sented to it by the outward senses. 



Further ; we see in Plato, that one of the grounds of the failure in 

 this attempt, was the assumption that the reason tuhy every thing is 

 what it is and as it is, must be that so it is best, according to some 

 view of better or worse attainable by man. Socrates, in his dying 

 conversation, as given in the Phcedo, declares this to have been what 

 he sought in the philosophy of his time; and tells his friends that he 

 turned away from the speculations of Anaxagoras because they did not 

 give him such reasons for the constitution of the world ; and Plato's 

 Timceus is, in reality, an attempt to supply this deficiency, and to 

 present a Theory of the Universe, in which every thing is accounted 

 for by such reasons. Though this is a failure, it is a noble as well as 

 an instructive failure. 



