TWO:In their theory of cognition the Stoics chiefly followed Aristotle; only with them the doctrine of empiricism is enunciated so distinctly as to be placed beyond the reach of misinterpretation. The mind is at first a tabula rasa, and all our ideas are derived exclusively from the senses.37 But while knowledge as a whole rests on sense, the validity of each particular sense-perception must be determined by an appeal to reason, in other words, to the totality of our acquired experience.38 So also the first principles of reasoning are not to be postulated, with Aristotle, as immediately and unconditionally certain; they are to be assumed as hypothetically true and gradually tested by the consequences deducible from them.39 Both principles well illustrate the synthetic method of the Stoicstheir habit of bringing into close16 connexion whatever Aristotle had studiously held apart. And we must maintain, in opposition to the German critics, that their method marks a real advance on his. It ought at any rate to find more favour with the experiential school of modern science, with those who hold that the highest mathematical and physical laws are proved, not by the impossibility of conceiving their contradictories, but by their close agreement with all the facts accessible to our observation.On passing from the ultimate elements of matter to those immense aggregates which surpass man in size and complexity as much as the atoms fall below him, but on whose energies his dependence is no less helpless and completethe infinite worlds typified for us by this one system wherein we dwell, with its solid earthly nucleus surrounded by rolling orbs of lightLucretius still carries with him the analogies of life; but in proportion to the magnitude and remoteness of the objects examined, his grasp seems to grow less firm and his touch less sure. In marked contrast to Plato, Aristotle, and the Stoics, he argues passionately against the ascription of a beneficent purpose to the constitution of the world; but his reasonings are based solely on its imperfect adaptation to the necessities of human existence. With equal vigour he maintains, apparently against Aristotle, that the present system has had a beginning; against both Aristotle and Plato that, in common with all systems, it will have an enda perfectly true con111clusion, but evidently based on nothing stronger than the analogies of vital phenomena. And everywhere the subjective standpoint, making man the universal measure, is equally marked. Because our knowledge of history does not go far back, we cannot be far removed from its absolute beginning; and the history of the human race must measure the duration of the visible world. The earth is conceived as a mother bringing forth every species of living creature from her teeming bosom; and not only that, but a nursing mother feeding her young offspring with abundant streams of milkan unexpected adaptation from the myth of a golden age. If we no longer witness such wonderful displays of fertility, the same elastic method is invoked to explain their cessation. The world, like other animals, is growing old and effete. The exhaustion of Italian agriculture is adduced as a sign of the worlds decrepitude with no less confidence than the freshness of Italian poetry as a sign of its youth. The vast process of cosmic change, with its infinite cycles of aggregation and dissolution, does but repeat on an overwhelming scale the familiar sequences of birth and death in animal species. Even the rising and setting of the heavenly bodies and the phases of the moon may, it is argued, result from a similar succession of perishing individuals, although we take them for different appearances of a single unalterable sphere.207
Pellentesque habitant morbi tristique senectus et netus et
malesuada fames ac turpis egestas.
