Sri Aurobindo
Letters of Sri Aurobindo
5. On Three Works of the Mother
“The intellect that believes too much in its own importance and wants satisfaction for its own sake, is an obstacle to the higher realisation.
But this is true not in any special sense or for the intellect alone, but generally and of other faculties as well. For example, people do not regard an all-engrossing satisfaction of the vital desires or the animal appetites as a virtue; the moral sense is accepted as a mentor to tell one the bounds that one may not transgress. It is only in his intellectual activities that man thinks he can do without any such mentor or censor!” [p. 33]
The subject is too large for any special instances to be usefully given, as an instance can only illustrate one side or field of a very various action. The point is that people take no trouble to see whether their intellect is giving them right thoughts, right conclusions, right views on things and persons, right indications about their conduct or course of action. They have their idea and accept it as truth or follow it simply because it is their idea. 
Even when they recognise that they have made mistakes of the mind, they do not consider it of any importance nor do they try to be more careful mentally than before. In the vital field people know that they must not follow their desires or impulses without check or control, they know that they ought to have a conscience or a moral sense which discriminates what they can or should do and what they cannot or should not do; in the field of intellect no such care is taken. Men are supposed to follow their intellect, to have and assert their own ideas right or wrong without any control; the intellect, it is said, is man’s highest instrument and he must think and act according to its ideas. But this is not true; the intellect needs an inner light to guide, check and control it quite as much as the vital. There is something above the intellect which one has to discover and the intellect should be only an intermediary for the action of that source of true Knowledge.
23 March 1937