The same rivalry made itself felt in the sphere of philosophy, and the Franciscans dealt a heavy blow at their more orthodox adversaries by impugning successfully an important doctrine of Thomas Aquinas[498]. The Angelic Doctor had held with Aristotle and against Averroes that the individualising principle was not form but matter. How then, asked his opponents, could the individual exist in the non-material world[499]? Such a doctrine was in contradiction to the mediaeval theory of heaven and the life after death; and the Church rallied to the side of the Franciscans. At Oxford, Archbishop Kilwardby, Dominican though he was, condemned this among many other errors in 1276, but the sentence seems to have had little effect at the time[500]. It was chiefly against this opinion that Peckham’s measures in 1284 were directed[501]. If the Dominicans had allowed the aspersion cast on their greatest teacher to pass without serious protest when the condemnation came from one of themselves, they were anything but content to submit to the adverse judgment of one of their rivals. Peckham was attacked both by the Provincial of the Black Friars in a congregation at Oxford[502] and in an anonymous pamphlet apparently by a Cambridge Dominican[503]--‘a cursed page and infamous leaf,’ as he describes it, ‘whose beginning is headless, whose middle malignant, and whose end foolish and formless.’ His action further involved the whole of the Franciscan Order in England in the storm. He was accused of ‘having sown discord between the Orders[504];’ and to defend himself against the charge of unduly favouring the Franciscans, he denied that he had consulted the latter on the subject and insisted on the previous condemnation of the same error by his predecessor[505]. He claimed to be actuated by no personal animus against the dead, whom he held in high honour and whom he had himself defended; his attack was directed against ignorant and arrogant men who presumed to teach what they did not know and to entice youths to the same errors. ‘We cannot and dare not,’ he urged, ‘fail to rescue our children, as far as we can, from the traps of error;’ and he forbade ‘curious theologians’ to defend the condemned doctrines in ‘the disputes of boys’ (_in certaminibus puerilibus_) at Oxford.