The wealth of the State, he says, is the labor of its subjects, and they work because the wants of man are not a stated sum, but "multiply every moment upon him." The desire for wealth comes from the idea of pleasure; and in the _Treatise on Human Nature_ he discusses with superb clarity the way in which the idea of pleasure is related at once to individual satisfaction and to that sympathy for others which is one of the roots of social existence.

He points out the need for happiness in work.

"The mind," he writes, "acquires new vigor, enlarges its powers and faculties, and by an assiduity in honest industry both satisfies its own appetites and prevents growth of unnatural ones"; though, like his predecessor, Francis Hutcheson, he overemphasizes the delights opened by civilization to the humbler class of men.

He gives large space in his discussion to the power of will; and, indeed, one of the main advantages he ascribed to government was the compulsion it puts upon us to allow the categories of time and space a part in our calculations.

He does not, being in his own life entirely free from avarice, regard the appetite for riches as man's main motive to existence; though no one was more urgent in his insistence that "the avidity of acquiring goods and possessions for ourselves and our nearest friends is ...