[59] The possibility of such a result would depend upon two assumptions, which are not in accordance with reality, and for which allowance must be made. The first is the assumption that the labouring population is stationary; the second is that Ability can increase the productivity of Labour equally in all industries. In reality, however, as was noticed in the last chapter, the number of labourers increases constantly, and the improvements in different industries are very unequal; and, owing to these two causes, it often happens that the total value produced in some industries by Labour and Ability together is not so great as is the share that is taken by Labour in others. Thus the labourers employed in the inferior industries could by no possibility raise their wages to the amount received by the labourers employed in the superior ones. Their effort accordingly would be to obtain employment in the latter, and to do so by accepting wages higher indeed than what they receive at present, but lower than those received by the men whose positions they wish to take. Thus, under such circumstances, a union of industrial interests ceases to be any longer possible. By an irresistible and automatic process, there is produced an antagonism between them; and the labourers who enjoy the higher wages will do what is actually done by our Trade Unions: they will form a separate combination to protect their own interests, not only against the employers, but even more directly against other labourers. At a certain stage of their demands, the labourers may be able to combine more readily and more closely than the employers; but when a certain stage has been passed, the case will be the reverse. The employers will be forced more and more into unanimous action, whilst the labourers, by their diverging interests, are divided into groups whose action is mutually hostile. [60] The reader must always bear in mind the definition given of Labour, as that kind of industrial exertion which is applied to one task at a time only, and while so applied begins and ends with that task; as distinguished from Ability, which influences simultaneously an indefinite number of tasks.