Here, another state of al-ʿaql is indicated, namely al-ʿaql al-salīm, by reaching which ʿaql gains superiority over all things. Al-ʿaql al-salīm in its ordinary connotation, would amount to commonsense. Its Arabic connotation, in the strict sense, signifies ʿaql that is free from obstruction. In other words, ʿaql that is protected. ʿAql in man, we have already noticed, is inherently a tainted potentiality, which by the force of outside evil influences, may be further tainted or made impure in the absence of conditioning and purification. Such impurity obstructs ʿaql, i.e, affects its common sense quality.
History narrates cases of tyrants who claimed to be guided by common sense but who nevertheless followed a trail of destruction and pillage. Man’s endeavour should be to eliminate all obstructions whatsoever which beset the path of ʿaql and so raise it to the character of al-ʿaql al-salīm. The author’s entire discourse is intended to indicate how this state, namely, that of al-ʿaql al-salīm, may be achieved by man.