a Greek philosopher who flourished in the third century B.C., was the son of Arcesilaus, of Lampsacus. He belonged to the Aristotelian school, and in 286 B.C. was appointed by Theophrastus, the immediate successor of Aristotle, to succeed him as head of the Lyceum. This position he held for eighteen years; and he is also said to have instructed Ptolemy Philadelphus in philosophy. Strato devoted his attention chiefly to physical science, and on that account was known by the surname of Physicus, or the naturalist. A list of his works given by Diogenes shows that only a few of them were devoted to any other than physical subjects. No authentic fragments of his writings have been preserved, and we can only form some imperfect idea of his teaching from incidental notices in other authors. He seems to have introduced some modifications of the peripatetic philosophy, which were afterwards more fully developed in the epicurean system. In psychology he carried to a greater length the tendency which had been previously begun by Theophrastus; to represent the purely intellectual acts of the mind as much more closely allied to sensation than Aristotle had admitted. The mind, according to him, in pure thought no less than in sensation, makes use of the material organism; and these two operations, though distinct from each other, can never be carried on separately. Consequently, if Strato adhered to Aristotle's view as to the perishable nature of the lower or sensational part of the soul, he could not have held in any sense its immortality. The metaphysical opinions of Strato are not so certainly known as his psychological views, and they have given rise to considerable discussion in modern times. The peculiarity of his doctrine was, that the self-moving power of nature is, as it were, dormant, until it is called into action by something from without. Cudworth, Leibnitz, Bayle, and others have accused Strato of atheism; but he has not been without defenders from this charge. The few and brief notices we have on this subject from ancient writers do not perhaps warrant us in coming to any decided conclusion.