I know not whether this inquiry I speak of concerning the first condition of seeds or atoms be not the most useful of all." — BACON.
THE popular conception of any philosophical doctrine is necessarily imperfect, and very generally unjust. Lucretius is often alluded to as an atheistical writer, who held the silly opinion that the universe was the result of a fortuitous concourse of atoms readers are asked to consider how long letters must be shaken in a bag before a complete annotated edition of Shakespeare could result from the process; and after being reminded how much more complex the universe is than the works of Shakespeare, they are expected to hold Lucretius, with his teachers and his followers, in derision. A nickname which sticks has generally some truth in it, and so has the above view, but it would be unjust to form our judgment of a man from his nickname alone, and we may profitably consider what the real tenets of Lucretius were, especially now that men of science are beginning, after a long pause in the inquiry, once more eagerly to attempt some explanation of the ultimate constitution of matter.
This problem, a favourite one with many great men, has come to be looked upon by most persons as insoluble nay, the attempt to solve it is sometimes treated as impious; but knowing that all the phenomena of light are explained by particular motions of a medium constituted according to simple laws, and so perfectly explained that the exact motions corresponding to all the colours of the spectrum, with their modifications due to reflection, refraction, and polarization, can be defined in form, 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 assumption the existence of some original material possessing properties 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 knowledge, 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 [212] 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.