The issue of materialism has recently been raised again. Mr. Putnam argues against philosophical behaviorism [4]. Such a position holds, as he construes it, that statements like ‘Jones is angry’ can be analyzed in solely behavioral terms. When one argues against philosophical behaviorism, he might be expected to distinguish this metaphysical position from behavior science. Putnam, however, does not make the distinction. Consequently he argues against both. I shall first state the distinction between these two different things, namely, philosophical behaviorism and behavior science, as I see it. The behavior scientist adopts the thesis that in principle it is possible to predict future behavior on the basis of data concerning environmental, behavioral, and physiological variables. All three of these he considers in physical terms. The behavior scientist thus speaks about physical objects and properties of such. Talking in such terms, he believes that it is in principle possible to coordinate to statements asserting that person X has or is in state of mind Y another statement, employing only the above mentioned physical terms, such that either both are true or both are false. The reasons for the behavior scientist's program are the well known quandaries involved in the observation of other people's minds and the need for intersubjective verification in science. One can further distinguish between a narrower and a broader view of behavior science. The former restricts itself to environmental and behavioral variables at what some call the macro level; the latter includes, or even concentrates upon, physiological variables. As scientists neither the behaviorist nor the physiologist asks or answers philosophical questions, either epistemological or ontological, about minds, bodies, and mental contents.