But Lucretius and the school to which he belonged did not look forward to a steady and continuous process of further amelioration in the future. They believed that a time would come when the universe would fall into ruins, [Footnote: Ib. 95.] but the intervening period did not interest them. Like many other philosophers, they thought that their own philosophy was the final word on the universe, and they did not contemplate the possibility that important advances in knowledge might be achieved by subsequent generations. And, in any case, their scope was entirely individualistic; all their speculations were subsidiary to the aim of rendering the life of the individual as tolerable as possible here and now. Their philosophy, like Stoicism, was a philosophy of resignation; it was thoroughly pessimistic and therefore incompatible with the idea of Progress. Lucretius himself allows an underlying feeling of scepticism as to the value of civilisation occasionally to escape. [Footnote: His eadem sunt omnia semper (iii. 945) is the constant refrain of Marcus Aurelius.] Indeed, it might be said that in the mentality of the ancient Greeks there was a strain which would have rendered them indisposed to take such an idea seriously, if it had been propounded. No period of their history could be described as an age of optimism. They were never, by their achievements in art or literature, in mathematics or philosophy, exalted into self-complacency or lured into setting high hopes on human capacity. Man has resourcefulness to meet everything--[words in Greek],--they did not go further than that. This instinctive pessimism of the Greeks had a religious tinge which perhaps even the Epicureans found it hard entirely to expunge. They always felt that they were in the presence of unknown incalculable powers, and that subtle dangers lurked in human achievements and gains. Horace has taken this feeling as the motif of a criticism on man's inventive powers. A voyage of Virgil suggests the reflection that his friend's life would not be exposed to hazards on the high seas if the art of navigation had never been discovered--if man had submissively respected the limits imposed by nature. But man is audacious: Nequiquam deus abscidit Prudens oceano dissociabili Terras. In vain a wise god sever'd lands By the dissociating sea. Daedalus violated the air, as Hercules invaded hell. The discovery of fire put us in possession of a forbidden secret. Is this unnatural conquest of nature safe or wise? Nil mortalibus ardui est: Man finds no feat too hard or high; Heaven is not safe from man's desire. Our rash designs move Jove to ire, He dares not lay his thunder by.