In the earlier, or rather in all but the late phases of culture and technology, this immaterial equipment at large is accessible to all members of the community as a matter of course through the unavoidable discipline that comes with the workday routine of getting along. Few, if any, can avoid acquiring the essential elements of the industrial scheme by use of which the community lives, although they need not each gain any degree of proficiency in all the manual operations or industrial processes in which this technological scheme goes into effect, and few can avoid being so trained into the logic of the current scheme that their habitual thinking will in all these bearings run within the bounds of experience embodied in this general scheme. All have free access to this common stock of immaterial equipment, but in all known cultures there is also found some degree of special training and some appreciable specialisation of knowledge and occupations; which is carried forward by expert workmen whose peculiar and exceptional proficiency is confined to some one or a few distinct lines of craft. And in all, or at least in all but the lowest known cultures, the available evidence goes to say that this joint stock of technological mastery can be maintained and carried forward only by way of some such specialisation of training and differentiation of employments. No one is competent to acquire such mastery of all the lines of industry included in the general scheme as would enable him (or her) to transmit the state of the industrial arts to succeeding generations unimpaired at all points. Some degree of specialisation there always is, even where there appears to be no urgent technological need of it. The circumstances of their life differ sufficiently for different individuals, so that a certain individuation in workmanship will result from commonplace experience, even apart from any deliberate specialisation of occupations. And with any considerable increase in the size of the group a more or less deliberate specialisation of occupations will also set in. Individuals who are in this way occupied wholly or mainly with some one particular line of work will carry proficiency in this line to a higher pitch than the generality of workmen and will bring out details of technological procedure that may never fully become the common possession of the group at large, that may not in all details become part of the commonplace technological information current in the community. There seems, in fact, never to have been a time when the industrial scheme was so slight and narrow that all members of the community could master it in the greatest feasible degree of proficiency at every point. But at the same time it holds true for all the more archaic phases of the development that all members of the community appear always to have had a comprehensive and passably exhaustive acquaintance with the technique of all industries practised in their time.