244 THOMAS WHITTAKER: just as learning was to him material for the expression of his metaphysical ideas, so science was a means of arriving at a true conception of nature as a whole. But in order to illustrate his mode of thought in dealing with special scien- tific questions, his theory of the causes of the present dis- tribution of life on the earth may be referred to. He holds that the earth, under the influence of the light and heat of the sun, has the power of producing all forms of life from any part of itself, provided that the proper kinds of matter are present there. It is not necessary, he says, to suppose that all men are descended from the same an- cestor ; nor is each of the other races of animals descended from a common ancestor ; all kinds of animals were pro- duced in all parts of the earth. But in different places different kinds of animals have been destroyed and different kinds have remained ; as in England, for example, certain kinds of wild animals have been destroyed, through the cultivation of the country by men, and in other islands all men have perished through the predominance of the more powerful animals or through lack of food. 1 The mode of thinking that has since given origin to the theory of natural selection is obviously expressing itself here under the limitations imposed by the state of the sciences of life in the sixteenth century. Bruno has speculated in the same spirit oil the reason of the distances maintained by the different planetary systems from one another. 2 He has himself indicated the relation of this speculation to the ancient speculations as to the survival of certain combina- tions of atoms. He had a great admiration for Lucretius and imitated him in his later Latin works. He sometimes speaks of atoms as the " first bodies," the only solid parts of the world. Atomic speculations, however, are subordinate in Bruno's philosophy. He himself, in the passage just referred to and in other places, distinguishes his doctrine from that of Dernocritus. He points out that while Democritus regarded life and mind as accidental products of certain combinations of atoms, he on the contrary regards them as equally eternal with atoms. He often quotes the following lines from Virgil as an expression of the doctrine he opposes to that of the Epicurean school : Principio coelum ac terras coraposque liquentes, Lucentemque globum lunae, Titaniaque astra, Spiritus intus alit, totamque infusa per artus Mens agitat molem, et magno se corpore miscet. 1 De Immense, vii., c. 18. - De Immenso, v., c. 3.
