William Barrett helped to introduce existentialism to American philosophers with his book Irrational Man in 1958.

In 1986 his book The Death of the Soul described the "scientistic" attempts to reduce humans to machines and the brain to a computer.

Barrett traced this approach back to Alfred North Whitehead who called it "scientific materialism."

For both Whitehead and Barrett, the recovery of the soul seemed to require traditional religious and theological explanations of an immaterial soul, which was the solution for René Descartes, who introduced dualism and the "mind-body problem in the first place.

Psychology has struggled for decades to establish a "science of the mind," first by "introspecting" what is going on inside the mind, then adopting "behaviorism" which denies the existence of the unobservable immaterial mind and allows only verifiable "observations of human behavior," then replacing behaviorism with "cognitive science," and finally neuroscience, which is now measuring observable changes inside the brain that are correlated with various aspects of consciousness.

Barrett makes the case that in the "modern age" this "scientistic" psychology has "banished consciousness."

When did this Modern Age begin? Historical epochs merge into one another, and it may be arbitrary to seek for points of absolute beginning. When, for example, did the Middle Ages begin? When end? It would be futile here to seek an absolute point of division between the past and the epoch that succeeded it. But sometimes there are points at which we can see clearly that by this time something new has already arrived and is bound to transform human history radically. Accordingly, we may take the beginning of our Modern Age to be the early-seventeenth century. For that was the century that created modern science and its accompanying technology; and these two, science and technology, have become, as we have seen, the driving forces within modern civilization.

What is modern science? As often as we have asked and answered this question, we need to rethink it again as we approach the end of the millennium in which that science has decisively transformed human life. We shall have more to say on this question in a later chapter. Suffice it here simply to note that, whatever else it may be, science is an exhibition of the power of the human mind, of its freedom and originality to construct concepts that are not passively found in nature but nevertheless serve to organize our experience of nature. Thus the existence of a body of science is in itself a powerful evidence of human freedom.

Yet here a curious paradox arises. Mechanics was a central part of the new physics; until mechanics was firmly established, physics could not get under way. But the science of mechanics was no sooner founded than a widespread ideology of mechanism followed in its wake. Man is a machine, so the lament goes. The molecules in nature blindly run according to the inalterable mechanical laws of nature; and as our molecules go, so do we. The human mind is a passive and helpless pawn pushed around by the forces of nature. Freedom is an illusion. And this lament was to rise to a crescendo of pessimism during the nineteenth century.

In short, no sooner has science entered the modern world than it becomes dogged by its shadow, scientism. What is this peculiar phenomenon we call scientism? It is not science, any more than the shadow is anywhere identical with the substance of a thing. Nor is science ever evidence of scientism. At most, science merely serves to heat up the imagination of certain minds—and they are not few—who are too prone to sweeping and unqualified generalizations in the first place. ^Scientism is pseudoscience or misinterpreted science. Its conclusions are sweeping and large, and therefore sometimes pretend to be philosophical. But it is not a part of philosophy, if by philosophy we mean the effort to think soberly within the restrictions that human reflection must impose for itself. No; scientism is neither science nor philosophy, but that peculiarly modern invention and malady—an ideology. And as such, along with other ideologies that beset us, it has become a permanent part of our modern culture.

The science which the seventeenth century sought was chiefly physics, the understanding of physical nature. But at the same time, as the science of nature blossoms, the theories of mind that sprout among philosophers become more paradoxical and at odds with each other. It is as if the thinkers who had reared this dazzling structure of the new science were more and more puzzled to understand the mind that had produced it. The situation has not improved since. In the three and a half centuries since modern science entered the world, we have added immeasurably to our knowledge of physical nature, in scope, depth, and subtlety. But our understanding of human consciousness in this time has become more fragmentary and bizarre, until at present we seem in danger of losing any intelligent grasp of the human mind altogether.

It may be worthwhile, then, to take a step backward and try to see how this situation has come about. For this purpose we need not burden the reader with heavy and excessive historical detail. We shall be pursuing a single theme throughout, and we shall make use of only as much history as may serve to establish its thematic clarity. Nor shall we be seeking here to establish any new "theory of mind,” whatever that might be. Such theories, in their ingenuity, sometimes lose their grasp on the very fact of consciousness itself as they seek to replace it by something different; and what we shall be trying here to do is simply to lay hold of the fact itself, the fact of consciousness as a human reality that seems on the way to getting lost in the modern world.

The Death of the Soul. pp. xiv-xvi.