Ibn Roshd's Theory of the Unity of the Intellect (Rational Soul) and the Denial of the Individual Immortality

Ibn Roshd (Averroes) maintains the unity of the intellect (rational soul) in all humans, which leads to the denial of the individual immortality. Proponents of Ibn Roshd admitted consequence and in order to defend this view along with the doctrine of individual immortality they had to subscribe to the weird theory of the double truth (the possibility of the truth of two contradictory propositions in two different domains). The source of the theory of the intellectual unity is in Aristotle’s view of the active and passive intellects. According to Ibn Roshd’s interpretation of Aristotle, the active intellect is –besides the passive one- an intellect which separates from the human body at death and enjoys an immortal life. However given the fact that the active intellect is numerically one and it is not the case that each human person has their own active intellect and the passive intellect dies with the death of the body, we should come to the conclusion that the theory of intellectual unity entails the denial of the individual immortality. According to this theory, what remains after death, is one universal immaterial entity (the active intellect). Ibn Roshd has sometimes been explicit on this consequence. The underlying reason for this claim is that the source of numerical plurality is matter; therefore, if the soul is immortal, there will only be one soul when the bodies disappear. Nonetheless Ibn Roshd proposes the possibility of there being a fine-grained matter, which might be the grounds for the plurality of the souls after death.