Max Delbrück was a physicist turned biophysicist as a result of Niels Bohr's lectures on complementarity and "Light and Life." Bohr suggested a complementary relation between the physical and physiological analogous to that between the wave and particle views in quantum mechanics. Although he never found the equivalent of an uncertainty principle in biology, Delbrück's research into bacteriophages (viruses) in the 1930's and early 1940's won him the Nobel prize for discovering that bacteria become resistant to viruses as a result of genetic mutations. This emphasis on mutations led Erwin Schrödinger to devote a large part of his 1945 essay "What Is Life?" to Delbrück's work, which made him famous very quickly. Schrödinger guessed that the genetic hereditary material might be an "aperiodic crystal" and this inspired James Watson and Francis Crick to discover the double helix architecture of DNA. The 1986 book, Mind from Matter?, was edited posthumously from audio tapes of Delbrück's CalTech biology course, given in the mid 1970's. The course included twenty lectures that he called "evolutionary epistemology." It is unlikely that Delbrück knew of the similarly titled work of Donald Campbell or Karl Popper (or vice versa).
We begin our epistemological inquiry from the viewpoint of naive realism and consider our problem of truth and reality in the light of evolution. So we ask three naive questions: 1. How can we construct a theory of a universe without life, and therefore without mind, and then expect life and mind to evolve, somehow, from this lifeless and mindless beginning? 2. How can we conceive of the evolution of organisms with mind strictly as an adaptive response to selective pressures favoring specimens able to cope with life in the cave, and then expect that this mind is capable of elaborating the most profound insights into mathematics, cosmology, matter, and the general organization of life and mind itself? 3. Indeed, does it even make sense to posit that the capacity to know truth can arise from dead matter?The principal adaptive response that Delbrück studied was the basis of perception, which is needed to understand awareness of the environment, the picture of the environment stored in the mind as information about experience, and ultimately the consciousness of the mind.
The unity and continuity of life on earth is manifest in its molecular anatomy. All modern forms of life use nucleic acids as information stores and proteins as agents for the direction of biochemical reactions, with the same processes of transcription and translation mediating the expression of the stored information. The protein and nucleic acid constituents are universal, as is the genetic code, which determines how information stored as nucleotide sequences in long nucleic acid molecules is translated into the amino acid sequences of proteins. Eukaryotes and prokaryotes also share certain special molecules, for instance heme for electron transport, chlorophyll for photosynthesis, ATP for energy storage, and riboflavin for the catalysis of oxidation-reduction reactions and for sensing the presence of light. The unity and continuity of life is equally manifest in its psychic aspects. Perception in plants and animals is a familiar phenomenon, but the beginnings of perception are also clearly present in microorganisms, in which adaptive behavior demonstrates that they can detect and evaluate signals from the environment and respond appropriately. For example, chemoreception — the ability to sense and respond to changes in the chemical composition of the environment — is manifest in the swimming pattern of chemotactic bacteria. The path of a swimming bacterium corresponds to a random walk: runs of orderly swimming along a straight path are interrupted from time to time by a tumbling motion, resulting in the random selection of a new direction for the next straight run.Delbrück wonders how much progress he has made on explaining how mind evolved from matter, and the fundamental mind-body problem that he called the "Cartesian Cut."
Have we, then, answered the naive question we posed at the outset? Did we explain how mind evolved from no mind? Did we find out why so much more was delivered than was ordered, that is, how the mind, having evolved for using stone tools, mounting a minimum of social organization for the hunt, and telling tales about hunting around the hearth, managed to get us to the abstruse reaches of number theory, relativity and quantum theory, elementary particles, and molecular genetics, not to speak of getting us to the moon? Maybe we didn't give any straight answers to these questions, but I think the dilemma "mind from no mind" looks less perplexing than it used to. On the one hand, neurobiological and psychophysical studies of subjective perception have provided insights into how we come to know the world, and cybernetics and even AI have helped a little to illuminate the nature of human thought processes. On the other hand, our ideas about the objective character of the physical world, and hence of the nature of truth have been revised. In other words, mind looks less psychic and matter looks less materialistic, especially in the light of Bohr's complementarity argument, which removed the illusion of total determination and objectivity. Part, but only part, of the solution to the riddle of how it is possible for the mind to deal so successfully with aspects of the world for dealing with which it was never selected may lie in a combination of fluctuation and illusion. The fluctuation arises from the vast amplification of simple knowledge through social organization. To fly to the moon does not require monumental intelligence; it requires the cooperation of 500,000 quite ordinary minds. The illusion arises from the preoccupation with our successes and the repression of our failures. The Stone Age people in England constructed Stonehenge 4000 to 5000 years ago, embodying some astronomical information in its architecture. They probably thought very highly of themselves. Little did they know how much they didn't know. Let us conclude with some general reflections on the peculiar role played by the sciences in this story. The classical natural sciences solidified the feeling that the adult human mind is an absolute: it grasps absolute physical laws concerned with absolute matter embedded in absolute space and time. The Cartesian cut between mind and matter is the rock on which such physical laws stand. Modern science has gone in the opposite direction. It has forced us to abandon absolute space and time, determinism, and the absolute object. It has shown that these naive notions are applicable only in the middle dimensions of space, time, and energy and must be replaced by more abstract formal schemes. As soon as we move to phenomena at extreme dimensions, our intuitions—that is, our concrete mental operations— become inadequate. This is the point, exactly, where evolutionary thinking is decisively helpful. It suggests, in fact it demands, that our concrete mental operations are indeed adaptations to the mode of life in which we had to compete for survival a long time before the development of science. As such we are saddled with them, just as we are with our organs of locomotion and our eyes and ears. But with science we can transcend our intuitions, just as with electronics we can transcend our eyes and ears. To the question of how the mental capacity for such transcendence can have arisen in the course of biological evolution I have no satisfactory answer. Indeed, the approach I have sketched in this essay by no means resolves all puzzles, nor does it produce a grand synthesis of the diverse universes of discourse now current in the various sciences. Least of all does it give a basis for a new setting of values in ethics relevant to the life of the individual or to social organization. The feeling of absurdity evoked by the question "mind from matter?" is perhaps similar to the feeling of absurdity with which we have learned to cope when we permit relativity theory to alter our intuitive concepts of time and space and quantum theory to alter our intuitive concepts of object and causality. If we can learn to accept this ultimate absurdity, there may yet be hope for developing a formal approach that will permit a grand synthesis.