I suggest two main ways of interpreting Reid's analysis of the perception of the quality of hardness: Reid endorses two distinct concepts of hardness. The distinction between the two lies in a profoundly different relation between the sensation of hardness and the concept of hardness in each of them. The first concept, which I term as a “sensation-laden concept”, is “the quality that arises in us the sensation of hardness.” The second concept, which I call a “non-sensational concept”, is “the (...) cohesion of the parts of the body with more or less force.” Reid is thinking like a developmental psychologist and postulates what I consider as a gradual development from one concept to the other according to which the initial sensation-laden concept of hardness, which we form during our early childhood, gradually develops into a mature non-sensational concept of hardness. (shrink)