This way of thinking is sometimes called ‘common sense.’  A good example of its application to politics may be found in a sentence from Macaulay’s celebrated attack on the Utilitarian followers of Bentham in the Edinburgh Review of March 1829.  This extreme instance of the foundation of politics upon dogmatic psychology is, curiously enough, part of an argument intended to show that ’it is utterly impossible to deduce the science of government from the principles of human nature.’  ‘What proposition,’ Macaulay asks, ’is there respecting human nature which is absolutely and universally true?  We know of only one:  and that is not only true, but identical; that men always act from self-interest.... When we see the actions of a man, we know with certainty what he thinks his interest to be.’[3] Macaulay believes himself to be opposing Benthamism root and branch, but is unconsciously adopting and exaggerating the assumption which Bentham shared with most of the other eighteenth and early nineteenth century philosophers—­that all motives result from the idea of some preconceived end.

[3] Edinburgh Review, March 1829, p. 185. (The italics are mine.)

If he had been pressed, Macaulay would probably have admitted that there are cases in which human acts and impulses to act occur independently of any idea of an end to be gained by them.  If I have a piece of grit in my eye and ask some one to take it out with the corner of his handkerchief, I generally close the eye as soon as the handkerchief comes near, and always feel a strong impulse to do so.  Nobody supposes that I close my eye because, after due consideration, I think it my interest to do so.  Nor do most men choose to run away in battle, to fall in love, or to talk about the weather in order to satisfy their desire for a preconceived end.  If, indeed, a man were followed through one ordinary day, without his knowing it, by a cinematographic camera and a phonograph, and if all his acts and sayings were reproduced before him next day, he would be astonished to find how few of them were the result of a deliberate search for the means of attaining ends.  He would, of course, see that much of his activity consisted in the half-conscious repetition, under the influence of habit, of movements which were originally more fully conscious.  But even if all cases of habit were excluded he would find that only a small proportion of the residue could be explained as being directly produced by an intellectual calculation.  If a record were also kept of those of his impulses and emotions which did not result in action, it would be seen that they were of the same kind as those which did, and that very few of them were preceded by that process which Macaulay takes for granted.

If Macaulay had been pressed still further, he would probably have admitted that even when an act is preceded by a calculation of ends and means, it is not the inevitable result of that calculation.  Even when we know what a man thinks it his interest to do, we do not know for certain what he will do.  The man who studies the Stock Exchange list does not buy his Debentures, unless, apart from his intellectual inference on the subject, he has an impulse to write to his stockbroker sufficiently strong to overcome another impulse to put the whole thing off till the next day.