The problem of liberty resolves itself therefore into that of the liberty of the mind. The coming achievement of economic independence is due largely to the circumstance that the Trade Unions have afforded a sanctuary for intellectual freedom against the danger of encroachment upon it by the system of private capital and the conditions of the machine industry.[21] It must, however, be remembered that the freedom of the mind is dependent on factors other than external; and chiefly upon the capacity to use mind in coherent and purposeful ways. A mind capable of such use will not long remain bound. This aspect of the problem belongs properly to the sphere of education; and it is in that setting only that it can be profitably handled. At this point our concern is with the external conditions of mental freedom. Footnote 21: It is worth noticing that on the other hand, the growth of the machine industry has itself indirectly co-operated in this process. “It follows as a consequence of the large and increasing requirements enforced by the machine technology that the period of preliminary training is necessarily longer, and the schooling demanded for general preparation grows unremittingly more exacting. So that, apart from all question of humanitarian sentiment or of popular fitness for democratic citizenship, it has become a matter of economic expediency, simply as a proposition in technological efficiency at large, to enforce the exemption of children from industrial employment until a later date and to extend their effective school age appreciably beyond what would once have been sufficient to meet all the commonplace requirements of skilled workmanship.” (Thorstein Veblen, _The Instinct of Workmanship_, p. 309.) This educational process has had consequences beyond those immediately sought. The quickening and enlargement of mind which have followed even the very inadequate education hitherto provided in the common schools, have made a very considerable contribution to the movement for economic emancipation. II