It will be seen that the justification for including Lucretius among the Pioneers of Evolution lies in his two signal and momentous contributions to the science of man; namely, the primitive savagery of the human race, and the origin of the belief in a soul and a future life. Concerning the first, anthropological research, in its vast accumulation of materials during the last sixty years, has done little more than fill in the outline which the insight of Lucretius enabled him to sketch. As to the second, he anticipates, well-nigh in detail, the ghost-theory of the origin of belief in spirits generally which Herbert Spencer and Dr. Tylor, following the lines laid down by Hume and Turgot (see p. 255), have formulated and sustained by an enormous mass of evidence. The credit thus due to Lucretius for the original ideas in his majestic poem--Greek in conception and Roman in execution--has been obscured in the general eclipse which that poem suffered for centuries through its anti-theological spirit. Grinding at the same philosophical mill, Aristotle, because of the theism assumed to be involved in his "perfecting principle," was cited as "a pillar of the faith" by the Fathers and Schoolmen; while Lucretius, because of his denial of design, was "anathema maranatha." Only in these days, when the far-reaching effects of the theory of evolution, supported by observation in every branch of inquiry, are apparent, are the merits of Lucretius as an original seer, more than as an expounder of the teachings of Empedocles and Epicurus, made clear. * * * * * Standing well-nigh on the threshold of the Christian era, we may pause to ask what is the sum of the speculation into the causes and nature of things which, begun in Ionia (with impulse more or less slight from the East, in the sixth century before Christ), by Thales, ceased, for many centuries, in the poem of Lucretius, thus covering an active period of about five hundred years. The caution not to see in these speculations more than an approximate approach to modern theories must be kept in mind. 1. There is a primary substance which abides amidst the general flux of things. _All modern research tends to show that the various combinations of matter are formed of some _prima materia_. But its ultimate nature remains unknown._ 2. Out of nothing comes nothing.