THE HUMAN PERSPECTIVE SIR CYRIL BURT* Politicians and leader-writers are again reminding us, in words that Adam doubtless used to Eve when they stumbled out of Paradise, that "Mankind is now at the Crossroads." As each generation has received the old warning, the complexity ofthe situation has progressively increased. Those to whom we now look for guidance—the social psychologist and the professional philosopher—seem generally agreed that a solution can best be reached by simply ignoring the more perplexing factors that combine to complicate the problem. In this, I venture to think, they are gravely mistaken. "The two stubborn facts that tend to defeat statesman and reformer alike," wrote Galton more than seventy years ago, "are each man's free choice and each man's fixed heredity—the one fully conscious, the other completely blind." The prevailing school ofphilosophy would have us to get rid of the word consciousness as "a meaningless concept in the physicalist 's world," or, as Professor RyIe puts it, "banish the ghost that haunts the machine." The sociologist assures us that, even if mental tendencies were inherited, we could still do nothing about it; so it is "best to regard mental differences—whether between individuals, communities, or races— as determined chiefly bytheirenvironment."Boththeseoversimplifications are a legacy from the Watsonian behaviourism; and, as a psychologist, I want, ifI can, to show that these two methodological principles, excellent as they may seem in the scientist's laboratory or the academic classroom, become highly misleading when carried over into practical life. I The immediate need ofthe scientist is to prove things, whereas that of the practical man is to understand things. His problem is to decide on a detailed policy; and for such a purpose a working understanding rather * University College, London, England. 317 than an impeccable proof is the fust prerequisite. The practical planner, therefore, must be prepared to accept bigger risks. The scientific theorist knows he will expose himselfto sharp criticisms from his colleagues ifhe puts forward any conclusion which is not as near to demonstrable certainty as an empirical conclusion can be. Hence he starts by applying Occam's methodological razor, and cuts down his initial unproved assumptions to the barest minimum. The framework within which he works—his "world-image" as the German scientist would call it—is consequently far simpler than that ofthe social or political practitioner. The conception ofthe universe that he has at the back ofhis mind was succinctly summed up by a late nineteenth century physicist as follows: "one kind ofelementary substance, namely matter, consisting ofone kind ofelementary particle with only one elementary property, namely mass, capable only ofone type ofelementary process, namely change in spatial location with passage oftime (or in a single word movement), resulting from only one kind offorce, namely mechanical force (or at least forces which all are reducible to mechanical forces), and operating in accordance with one universal law—the law ofstrict causal determination." In short, he pictures the cosmos as a gigantic machine. His final ideal—an ideal which numerous physicists from Newton and Laplace to Einstein and Heisenberg have hoped to achieve—is a single universal formula, something like Lagrange's celebrated equations, from which an omniscient observer could deduce both the past and the future ofthe whole universe. With this simple set of assumptions we can undoubtedly go a long way—particularly ifwe limit our investigations to what may be called man-sized phenomena—things possessing such magnitudes as we can perceive with our own unaided senses and moving with such speeds as we can follow with our own unaided eyes. But what these ultra-cautious postulates describe is not the concrete world as it is, but an abstract model of the world such as can be handled mathematically. One cannot think of oneself as living in such a model. And so, when we turn from the scientific study ofthe laws ofnature to the study ofthe history ofmankind, we find ourselves in an entirely different context. We are no longer watching a huge clockwork mechanism, unwinding surely and inexorably towards a predictable finish, in which at any given instant every tick and every motion is predetermined, with no conceivable alternative...