on the ground that their self-contradictoriness is demonstrable: the business of the philosopher, accordingly, is to substitute 'reasonable thinking' for 'common sense.' The 'raison impuissante,' emphasised by Hamilton—the ignorance in which Hamilton revels—is not allowed by Ferrier to be ignorance at all; for 'man cannot be said to be ignorant of self-contradictions that can be knowledge for no mind, human or divine.' Independent or unperceived matter is not merely hid from man’s knowledge on account of his 'raison impuissante'; it is hid from all intelligence, because inconsistent with the necessarily mind-dependent essence of Being. Pure reason does not need to be finally supplemented by practical principles of common sense. It is able to shift for itself without this surrender. The conciliation of common sense thinking and philosophy is accomplished by the submission of common sense to universal compulsory reason. Opinion must submit to demonstration, instead of demonstration, intelligible only by the few, having to make way for the undemonstrable dogmas of the unreflecting.
Reid, I suspect, could hardly recognise, in the stuffed figure thus put up by Ferrier to be knocked down, either the 'common sense' in which he found the root of a human knowledge of the realities revealed in place and time throughout the long experience of man, or the 'perception' in which things external to the individual mind make their appearance 'in part.' The practical impossibility of disbelieving the existence of other living beings, of discarding memory as wholly delusion, of treating man as irresponsible, and our surroundings as chaotic or wholly uninterpretable, alike for science and in common life—these were alleged constituents of the common sense with which Reid
