Ibn Rushd’s views do not receive much attention or criticism from Muslim scholars, but the Christian scholastics brought two main arguments against this theory, one psychological, the other theological. The psychological objection is that it is entirely subversive of individuality: if the conscious life of each is only part of the conscious life of a universal soul there can be no real _ego_ in any one of us; but there is no fact to which consciousness bears clearer witness than the reality and individuality of the _ego_. This did not touch the possibility that the individual soul might be drawn from a universal soul as its source, nor did it disprove that the individual soul might be reabsorbed again in the universal soul, but in so far as Ibn Rushd’s view represented the soul as throughout a part of the universal soul it was argued that this is contrary to experience, which makes it clear that in this present life the _ego_ is very distinctly individual. The theological argument was that Ibn Rushd’s view denied the immortality of the soul, and so was contrary to the Christian faith. This objection deals more specifically with the reabsorption of the soul of the individual in the universal soul; such cessation of separate and individual existence, it was argued, meant that the soul as such no longer existed. As we have already noted, Aristotle gives a rather narrow range to the highest faculty of reason, confining its activity to the perception of abstract ideas; “as to the things spoken of as abstract (the mind) thinks of them as it would of the being snub-nosed, if by an effort of thought it thinks of it _qua_ snub-nosed, not separately, but _qua_ hollow, without the flesh in which the hollowness is adherent: so when it thinks of mathematical forms, it thinks of them as separated, though they are not separated” (Aristot. _de anima._ iii. 7, 7-8). Those who followed Alexander Aph. and the neo-Platonists took this “abstract” in a very narrow sense, and in the Arabic commentators these abstractions even become non-substantial beings, as it were disembodied, or rather bodiless, spirits: “in quibusdam libris de Arabico translatis substantiae separatae, quae nos angelos dicimus, intelligentiae vocantur” (S. Thos. Aquin. _Quaest. Disp. de anima._ 16). Can man know these _substantiae separatae_ by his natural faculties? Ibn Rushd says he can: if otherwise nature has acted in vain, for there would be an _intelligibile_ without an _intelligens_ to understand it; but Aristotle has shewn (_Polit._ 1, 8, 12) that nature does nothing in vain, so that if there be an _intelligibile_ there must be an _intelligens_ capable of perceiving it. “The commentator (i.e. Ibn Rushd) says in 2 Met. comm. i. (in fine) that if abstract substances cannot be understood by us then nature has acted in vain, because it made that which is by nature understandable in itself to be not understood by anyone. But nothing is superfluous or in vain in nature.