The study of life at all levels, from the social to molecular behaviour, has in modern times relied on reductionism as the chief explanatory concept. This approach to knowledge tries to comprehend one level of scientific phenomena in terms of concepts at a lower and presumably more fundamental level. In chemistry, large-scale reactions are accounted for by examining the behaviour of molecules. Similarly, physiologists study the activity of living cells in terms of processes carried out by organelles and other subcellular entities. And in geology, the formations and properties of minerals are described using the features of the constituent crystals. The essence of these cases is seeking explanation in underlying structures and activities.
Reductionism at the psychological level is exemplified by the viewpoint in Carl Sagan’s best-selling book The Dragons of Eden. He writes: “My fundamental premise about the brain is that all its workings—what we sometimes call ‘mind’—are a consequence of its anatomy and physiology and nothing more.” As a further demonstration of this trend of thought, we note that Sagan’s glossary does not contain the words mind, consciousness, perception, awareness, or thought, but rather deals with entries such as synapse, lobotomy, proteins, and electrodes.
Such attempts to reduce human behaviour to its biological basis have a long history, beginning with early Darwinians and their contemporaries working in physiological psychology. Before the nineteenth-century, the mind-body duality, which was central to Descartes’ philosophy, had tended to place the human mind outside the domain of biology. Then the stress that the evolutionists placed on our “apeness” made us subject to biological study by methods appropriate to nonhuman primates and, by extension, to other animals. The Pavlovian school reinforced that theme, and it became a cornerstone of many behavioural theories. While no general agreement has emerged among psychologists as to how far reductionism should be carried, most will readily concede that our actions have hormonal, neurological, and physiological components. Although Sagan’s premise lies within a general tradition in psychology, it is radical in aiming at complete explanation in terms of the underlying level. This goal I take to be the thrust of his phrase “and nothing more.”
At the time various schools of psychology were attempting to reduce their science to biology, other life scientists were also looking for more basic levels of explanation. Their outlook can be seen in the writings of a popular spokesman of molecular biology, Francis Crick. In his book, Of Molecules and Men, a contemporary attack on vitalism—the doctrine that biology needs to be explained in terms of life forces lying outside the domain of physics—Crick states: “The ultimate aim of the modern movement in biology is in fact to explain all biology in terms of physics and chemistry.” He goes on to say that by physics and chemistry he refers to the atomic level, where our knowledge is secure. By use of the italicized all, he expresses the position of radical reductionism that has been the dominant viewpoint among an entire generation of biochemists and molecular biologists.
If we now combine psychological and biological reductionism and assume they are going to overlap, we end up with a sequence of explanation going from mind to anatomy and physiology, to cell physiology, to molecular biology, to atomic physics. All this knowledge is assumed to rest on a firm bedrock of understanding the laws of quantum physics, the newest and most complete theory of atomic structures and processes. Within this context, psychology becomes a branch of physics, a result that may cause some unease among both groups of professionals.
This attempt to explain everything about human beings in terms of the first principles of physical science is not a new idea and had reached a definitive position in the views of the mid-nineteenth-century European physiologists. A representative of that school, Emil Du Bois-Reymond, set forth his extreme opinions in the introduction to an 1848 book on animal electricity. He wrote that “if our methods only were sufficient, an analytical mechanics [Newtonian physics] of general life processes would be possible and fundamentally would reach even to the problem of the freedom of the will.”
There is a certain hubris in the words of these early savants that was picked up by Thomas Huxley and his colleagues in their defense of Darwinism and, even today, echoes in the theories of modern reductionists who would move from the mind to the first principles of atomic physics. It is most clearly seen at present in the writings of the sociobiologists, whose arguments animate the contemporary intellectual scene. In any case, Du Bois-Reymond’s views are consistent with modern radical reductionists, except that quantum mechanics has now replaced Newtonian mechanics as the underlying discipline.
During the period in which psychologists and biologists were steadily moving toward reducing their disciplines to the physical sciences, they were largely unaware of perspectives emerging from physics that cast an entirely new light on their understanding. Toward the close of the last century, physics presented a very ordered picture of the world, in which events unfolded in characteristic, regular ways, following Newton’s equations in mechanics and Maxwell’s in electricity. These processes moved inexorably, independent of the scientist, who was simply a spectator. Many physicists considered their subject as essentially complete.
Starting with the introduction of the theory of relativity by Albert Einstein in 1905, this neat picture was unceremoniously upset. The new theory postulated that observers in different systems moving with respect to each other, would perceive the world differently. The observer thus became involved in establishing physical reality. The scientist was losing the spectator’s role and becoming an active participant in the system under study.
With the development of quantum mechanics, the role of the observer became an even more central part of physical theory, an essential component in defining an event. The mind of the observer emerged as a necessary element in the structure of the theory. The implications of the developing paradigm greatly surprised early quantum physicists and led them to study epistemology and the philosophy of science. Never before in scientific history, to my knowledge, had all the leading contributors produced books and papers expounding the philosophical and humanistic meaning of their results.
Werner Heisenberg, one of the founders of the new physics, became deeply involved in the issues of philosophy and humanism. In Philosophical Problems of Quantum Physics, he wrote of physicists having to renounce thoughts of an objective time scale common to all observers, and of events in time and space that are independent of our ability to observe them. Heisenberg stressed that the laws of nature are no longer dealt with elementary particles, but with our knowledge of these particles—that is, with the contents of our minds. Erwin Schrödinger, the man who formulated the fundamental equation of quantum mathematics, wrote an extraordinary little book in 1958 called Mind and Matter. In this series of essays, he moved from the results of the new physics to a rather mystical view of the universe that he identified with the “perennial philosophy” of Aldous Huxley. Schrödinger was the first of the quantum theoreticians to express sympathy with the Upanishads and eastern philosophical thought. A growing body of literature now embodies this perspective, including two popular works, The Tao of Physics by Fritjof Capra and the Dancing Wu Li Masters by Gary Zukav.