Marx's conception of man's powers and of what is required for their realization provides the basis for his claim that man's activity (work, creativity) must be done with and for others, and, consequently, that he is a social being. Marx says that by ‘social’ he means ‘the cooperation of several individuals, no matter under what conditions, in what manner, and to what end’. This cooperation may be active, conscious and purposeful, as in production, or it may be passive, unconscious and without apparent purpose, as in using a language which other people understand. ‘Cooperation’, then, covers all the forms in and through which man relates to his fellows; but Marx also uses it in a narrow sense where it refers to joint activity aimed at achieving mutually accepted ends.

‘Society’, the last in Marx's trio of all-group expressions, is defined as ‘the sum of the relations in which … individuals stand to one another’. These relations are sometimes treated as existing externally to man, as when Marx calls society (the actual forms taken by cooperation) ‘the product of man's reciprocal activities’; and sometimes as lying within man himself, as when he says, ‘Society itself, that is man himself in his social relations’. And as people are seen related to each other not only directly but through their objects, the term ‘society’ at the limits of its definition covers both man and the world he inhabits.