Common-sense appears to be only another name for the thoughtlessness of the unthinking. It is made of the prejudices of childhood, the idiosyncrasies of individual character and the opinion of the newspapers.
Common sense always speaks too late. Common sense is the guy who tells you ought to have had your brakes relined last week before you smashed a front end this week. Common sense is the Monday morning quarterback who could have won the ball game if he had been on the team. But he never is. He's high up in the stands with a flask on his hip. Common sense is the little man in a gray suit who never makes a mistake in addition. But it's always somebody else's money he's adding up.
Common-sense is part of the home-made ideology of those who have been deprived of fundamental learning, of those who have been kept ignorant. This ideology is compounded from different sources: items that have survived from religion, items of empirical knowledge, items of protective skepticism, items culled for comfort from the superficial learning that is supplied. But the point is that common-sense can never teach itself, can never advance beyond its own limits, for as soon as the lack of fundamental learning has been made good, all items become questionable and the whole function of common-sense is destroyed. Common-sense can only exist as a category insofar as it can be distinguished from the spirit of inquiry, from philosophy.