Thus far, then, for the purposes of the present discussion, all parties are agreed; but the moment the assailants of interest take the next step in their argument, we shall find that their errors begin--errors resulting, as we shall see, from an imperfect analysis of facts. For them the two types of correspondence between productive effort and product are, firstly, the manual labourer, who performs some daily task such as riveting plates or bricklaying, and receives an equivalent in wages at the end of each day or week; and, secondly, the manager of some great industrial enterprise, who spends each day so many hours in his office, issuing minute directions with regard to the conduct of his subordinates, and sending his receipts to the bank as they come in from his customers. But these types, though accurate so far as they go, do but cover a part of the actual field of fact. Practically, though of course not absolutely, they ignore the element of time. They represent effort and product as being always so nearly simultaneous that, although the former must literally precede the latter, yet, if we estimate life in terms of years, or even months, or weeks, a man has ceased to produce as soon as he has ceased to work. Now, of certain forms of effort this may be true enough. A bricklayer, for example, as soon as he ceases to lay bricks, ceases to produce anything. His wall-building closes its effects with the walls which he himself has built. It does nothing to facilitate the building of other walls in the future. Similarly such ability as consists in a gift for personal management often ends its effects, and leaves no trace behind it, as soon as the manager possessing these gifts retires.