Platonism
It is possible to discern at least two widely different strands in the writings of Plato, the dogmatic and the critical: the Plato, in other words, who is responsible both for the theory of forms and the immortality of the soul on the one hand, and on the other the Plato who, in the tradition of his master Socrates, subjected all propositions to the sharpest criticism. Not long after his death in 347 the Academy which he had founded came under the influence of those who belonged for one reason or another to the second, sceptical stream. Partly in opposition to Stoic dogmatism, partly under the influence of Pyrrho, the leaders of the school, above all Arcesilaus (316/15-242/1) and Carneades, denied the possibility of any formal knowledge of anything. The last undisputed head of the Academy was Philo of Larissa (160/59-80), after whom, under the influence of his pupil Antiochus of Ascalon, the school lost its nerve and lapsed into dogmatism-a characteristic which it retained throughout the rest of its history right down to the closing of the (Boardman, 1986)