In this book it will be maintained that the conception of a group mind is useful and therefore valid; and, since this notion has already excited some opposition and criticism and is one that requires very careful definition, some attempt to define and justify it may usefully be made at the outset; though the completer justification is the substance of the whole book. Some writers have assumed the reality of what is called the ‘collective consciousness’ of a society, meaning thereby a unitary consciousness of the society over and above that of the individuals comprised within it. This conception is examined in Chapter II and provisionally rejected. But it is maintained that a society, when it enjoys a long life and becomes highly organised, acquires a structure and qualities which are largely independent of the qualities of the individuals who enter into its composition and take part for a brief time in its life. It becomes an organised system of forces which has a life of its own, tendencies of its own, a power of moulding all its component individuals, and a power of perpetuating itself as a self-identical system, subject only to slow and gradual change. In an earlier work, in which I have sketched in outline the program of psychology[4], I wrote: “When the student of behaviour has learnt from the various departments of psychology ... all that they can teach him of the structure, genesis, and modes of operation of the individual mind, a large field still awaits his exploration. If we put aside as unproven such speculations as that touched on at the end of the foregoing chapter (the view of James that the human mind can enter into an actual union or communion with the divine mind) and refuse to admit any modes of communication or influence between minds other than through the normal channels of sense-perception and bodily movement, we must nevertheless recognise the existence in a certain sense of over-individual or collective minds. We may fairly define a mind as an organised system of mental or purposive forces; and, in the sense so defined, every highly organised human society may properly be said to possess a collective mind. For the collective actions which constitute the history of any such society are conditioned by an organisation which can only be described in terms of mind, and which yet is not comprised within the mind of any individual; the society is rather constituted by the system of relations obtaining between the individual minds which are its units of composition. Under any given circumstances the actions of the society are, or may be, very different from the mere sum of the actions with which its several members would react to the situation in the absence of the system of relations which render them a society; or, in other words, the thinking and acting of each man, in so far as he thinks and acts as a member of a society, are very different from his thinking and acting as an isolated individual.”