THE CONDITIONED REFLEX: A MEANINGLESS CONCEPT ROBERT EFRON, M.D.* The terms "conditioning" and "conditioned reflex" have achieved such widespread usage, since their introduction by Pavlov, that the behavioral scientist presumably thinks that he "knows what he means" when he uses these words to describe, identify, or "explain" aspects of animal or human behavior. The recent vitriolic arguments between McConnell [i] who argues that worms can be "conditioned" and James and Halas [2] who argue thatMcConnell doesnot know thedifference between "true conditioning" and "pseudo-conditioning" should immediately suggest that the arguments are not concerned with the scientific observations (facts) but with the different meanings and implications which each author attaches to the concept "conditioned reflex." It is thepurpose ofthis paper to demonstrate (1) that the various debates about "conditioning" are not, as McConnell suggests, "semantic nonsense ," "question begging," or even "labelling problems," but represent profound epistemological chaos, that is, chaos in the realm of definitions and the logical relationships between concepts; (2) that the epistemological chaos originated as a consequence of the philosophical suppositions of mechanistic materialism which required biologists to exclude from the realm of "science" the concepts ofconsciousness, volition, and the causal efficacy ofmental processes; (3) that this policy led, in the twentieth century , to a progressive degradation of the concept of the "reflex"; (4) that the final degradation of the concept of the reflex was achieved by the introduction of the concept of the "conditioned reflex"; (5) that the "conditioned reflex," when defined in terms ofthe now-degraded concept ofthe "reflex" is without any scientific value, and when defined in terms * Chief, Neurophysiology-Biophysics Research Unit, Veterans Administration Hospital, Boston Massachusetts. 488 Robert Efron · The Conditioned Reflex Perspectives in Biology and Medicine · Summer 1966 of the original concept of the "reflex" is self-contradictory; (6) that all attempts to correct the semantic (linguistic) errors of this field (such as changing the phrase "conditioned reflex" to "conditioned response") without correcting the underlying epistemological errors, have led to even more profound confusion; and finally (7) that the conceptual errors latent in the mechanistic Cartesian view of animal behavior, extended to man by LaMettrie, made explicit by Sechenov, and brought to full development by Pavlov and Skinner (and their present-day followers) have had significance for biology only to the degree to which theyhave retarded its conceptual development. The fact that this debate about "conditioning" can occur one hundred years after the concepts were first introduced should serve as a warning signal to biologists, neurologists, and psychologists that these concepts must be re-examined. Therefore, let us turn to a detailed consideration ofthe concept ofa "reflex." I. The Reflex: Epistemological Considerations A "conditioned" or "conditional" reflex is the terminology which is used to refer to a special class ofreflexes. Logically, to call some aspect of animal or human behavior a "conditioned reflex," one would first have to show that the behavior in question has the specific attributes ofa reflex, and then show that it has the further specific attributes which permit finer classification into the subgroup to be called "conditioned reflexes." In an analysis ofthe concept "conditioned reflex," then, it is necessary to begin by being certain that we know to what we refer when we call some aspect ofanimal behavior a "reflex." The concept of the "reflex" was first formulated by Descartes in I049 [3]. He developed this mechanistic concept to give plausibility to his (prior) philosophical notion that the lower animals were merely complex automatons—machines which are devoid of mind and of volition. Descartes viewed animal behavior as similar in principle to the statues in the royal gardens which, when actuated by underground streams of water, made motions and sounds. One may very well compare the nerves of the machine which I am describing with the tubes of the machines of these fountains, the muscles and tendons of the machine with the other various engines and springs which serve to move these machines and the animal spirits, the source ofwhich is the heart and of which the ventricles are the reservoirs , with the water which puts them in motion [4]. 489 Descartes conceived of the animal's responses to sensory nerve stimulation as inevitable, machine-like, automatic...