The Future of Man— Evolutionary Aspects 
The mechanism of biological evolution is now, in broad outline, 
established. But we are only beginning to study psychosocial 
evolution in the same operational way. Some things, however, 
are becoming clear. In the first place, the basic elements in 
cultural transmission and transformation are psychological: 
they are patterns and systems of thought and attitude expressed 
or formulated in transmissible terms, from concepts to values. 
For want of a better word I shall lump them all together and 
call them zdeas. ‘The material elements transmitted—paintings, 
documents, machines, jewels—are normally vehicles or pro- 
ducts of ideas in this loose and general sense. 
A more precise term than psychological would be psychometa- 
bolic. Man is equipped with two metabolisms, two systems for 
transforming the raw materials of nature in serviceable ways. 
Physiological metabolism utilizes the raw materials of objective 
nature and elaborates them into biologically operative physico- 
chemical compounds and systems. Psychometabolism on the 
other hand utilizes the raw materials of subjective or mind- 
accompanied experience and elaborates them into psycho- 
socially operative organizations of thought and feeling— 
including principles like causation, categories like space, 
abstractions like truth; precepts and concepts, poems and gods, 
myths and scientific theories, moral commandments and legal 
codes. 
Psychometabolism introduces quality into a quantitative 
world, produces meaningful patterns out of the chaos of elemen- 
tary experience, and enables us to grasp extremely complex 
situations as wholes. Psychometabolic processes may become 
diseased, as in schizophrenics; their products may be unrelated 
to the objective world, as with hallucinations; they may be 
built on false foundations, like racialist ideas; or they may be 
rendered out of date by the march of knowledge, like the notion 
of demoniac possession: but they are a necessary part of our 
psychosocial machinery, and it behoves us to study them 
thoroughly and understand how they work. 
In psychosocial evolution the struggle for existence has been 
replaced by what might be termed the striving for fulfilment. 
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