1 78 SPECULATIVE SCIENCE 



speed, and magnitude knowing this, we may reasonably expect 

 that the other complex attributes of inorganic matter may be 

 deduced from some simple theory, involving only as an assump- 

 tion the existence of some original material possessing proper- 

 ties far less complex than those of the gross matter apparent to 

 our senses. It is only in this sense that we can hope ever to 

 understand the ultimate constitution of matter; but as the 

 undulatory theory of light has both suggested the discovery of 

 new facts, and has connected all known facts concerning light 

 into one intelligible series of logical deductions, so any true 

 theory of the constitution of matter would suggest new inquiries, 

 and would group the apparently disjointed fragments of know- 

 ledge, now called the various branches of science, into one 

 intelligible whole. To frame some such theory as this was the 

 first aim of Greek philosophers, and to establish the true theory 

 will be the greatest triumph of modern science. Of all the 

 subtle guesses made by the Greeks at this enigma, one only, 

 we think, has been fruitful, and that the one expounded by 

 Lucretius, but learnt by him from Epicurus, who in his turn 

 seems to have derived his most valuable conceptions from 

 Democritus and Leucippus. As, however, we possess fragments 

 only of these earlier writers, it is convenient to speak of the, 

 theory as that of Lucretius, though he seems to have been 

 simply the eloquent and clear expounder of a doctrine wholly 

 invented by others. 



Before explaining how far the views of Lucretius are still 

 held by naturalists, and how far they contain the germs of many 

 modern theories, we must endeavour to give a clear account of 

 what his views really were, in which attempt we shall be much 

 aided by the admirable edition and translation of his works by 

 Mr. Munro. 



The principles of the atomic theory are all contained in the 

 first two books ; attention being generally called in the original 

 to each new proposition by a ' mine agej or some such expres- 

 sion. Lucretius begins by stating that ' nothing is ever be- 

 gotten of nothing.' To this principle, which is assumed as true 

 in all physical treatises of the present day, he unnecessarily 

 adds, that this is not done even by divine power, about which 

 he could know nothing. Lucretius felt little reverence for the 



