Herbert Feigl, The "Mental" and the "Physical": The Essay and a Postscript (1967).
B. Non-Spatial versus Spatial.
The Cartesian distinction of res cognitans and res extensa still provides some philosophers of our age with what they consider one of their most powerful arguments in favor of a radical dualism. Mental states and events in contradistinction to physical bodies, so they claim, do not have a location, nor are they characterizable as having shapes or sizes. The apparent plausibility of this doctrine seems to me to derive mainly from (1) a confusion, and (2) inattention to phenomenal spatiality and its relations to physical spatiality. The confusion becomes evident in rhetorical questions asked by dualists, such as "where is the feeling of motherly love located?" "how many inches is it long?" "is it square or pentagonal?" I must confess I have little patience with these silly games. The feeling of motherly love is a universal, an abstract concept, and it makes as little sense to ask about its spatial location as it does in regard to the (physical) concept of temperature. We have here a category mistake of the crudest sort, a confusion between universals and individuals. It makes sense to ask about the location of individual things or events, but it is simply nonsense to ask about the location of a concept (properties or relations in abstracto).
The same sort of nonsense arises if, after hearing the sentence "the mental depression finally left him," someone asks, "Where did it go?" This sort of question can come only from taking the initial (metaphorical) statement as literally as we take "his wife finally left him." Concepts, whether they designate occurrent or dispositional properties, do not as such have spatial location; or rather it makes no sense to ascribe any such to them. But concepts which are constituents of singular (specific descriptive) statements1 are applied to individuals. We say "Anthony Eden felt depressed after the failure of the Egyptian campaign." In this case there is quite clearly a location for the feeling of depression. It is in the person concerned! The question of location becomes then more sensible, but logically also more delicate, if we ask it of individual mental states.
Using "mental" for the time being in the sense of "phenomenal", we had better -- and without too much ado -- introduce the indispensable distinction between phenomenal space(s) and physical space. I am perhaps not too acute in matters of phenomenological description but it does seem to me that my feelings and emotions pervade large parts of my body-as-I-experience it. William lames has given us some striking illustrations of this. In the phenomenal field of the subject, specific feelings may be located at least vaguely or diffusely in some not very sharply delimited part of the organism. My feelings or sentiments of elation, depression, delight, disgust, enthusiasm, indignation, admiration, contempt, etc. seem to me to be spread roughly through the upper half or two-thirds of my body.
Sounds and smells at least in the usual situations of "veridical" perceptions seem to be partly outside, partly inside the phenomenal head. Colors are usually perceived as surface qualities of extradermal objects, or in the case of looking at the skin of one's own arms or legs, as surface qualities of those limbs. Colors seen when pressing one's eyelids (closed eyes) are vaguely located either immediately in front of one's eyes, or even inside them. Similarly musical sound images (especially in the eidetic's case) either appear inside one's head or seem to come from the outside as in a concert hall. The taste of an apple is clearly experienced within the mouth. The stars as seen on a cloudless night are tiny bright spots on a fairly distant dark background. These bright spots clearly have spatial relations to one another. A given small portion of the sky-as-perceived is an approximately plane surface with the twinkling stars distributed in certain constellations. If for the moment we may use the names of the stars as proper names for the bright spots in the visual field, we may well say that, e.g., Sirius is to the left and far below the three stars of Orion's belt. There is no question then that we are "acquainted" with the elements and relations in visual space.
A detailed discussion of the differing features of visual, tactual, kinesthetic, and auditory "spaces" is a task for phenomenal psychology. For our purposes it is sufficient to notice that "spatiality" means qualitatively quite different things for the various sense modalities. But physical space, in the sense in which the science of physics (including, of course, astronomy) understands it, is something radically different. The astronomers' measurements and inferential interpretations have provided us with an account of the three-dimensional array of the stars in "objective" space. This three-dimensional order is most properly considered as a conceptual system which can be only inadequately visualized or imaged phenomenally. I don't for a moment deny that in our rooms or in a landscape we perceive directly at least some of this three-dimensional order. (In the case of the stars, we don't.) But what is present in perception at any given moment is always a particular perspective and not the geometrical order which we must assume (together with certain laws of geometrical optics) in order to explain the peculiarities of any (or all) particular perspectives.
I shall not labor the obviously analogous case of time. Phenomenal time and physical time differ from, and are related to, each other very much like phenomenal space and physical space. Experienced durations may seem very long in the case of tiresome waiting, while time packed full with exciting events seems to "pass quickly." But the physically measured durations may be exactly the same. The psychological relativity of (phenomenal) time must of course not be confused with the (Einsteinian) physical relativity of simultaneity and duration which, in the nature of the case, is not directly observable at all.2
We conclude then that mental data have their own (phenomenal) kinds of spatiality; and that physical space is a theoretical construction introduced to explain the features and regularities of phenomenally spatial relations. The exact and detailed derivation, even only of the perspectival aspects of visual spatiality is a quite complex matter, involving geometrical, physical, psychophysical, and psychophysiological laws. Our arguments have so far disproved only the Cartesian contention that the mental is non-spatial. To put it very strongly, mental events . as directly experienced and phenomenally described are spatial. Physical , bodies geometrically characterized in their measurable positions, orientations, shapes, and sizes are not spatial (in the visual, or generally, phenomenal) sense at all. "Space" in the physical sense is an abstract theoretical ordering system. The reader who accepts my arguments may nevertheless maintain that the emphasized distinction between phenomenal and physical spatiality (and temporality) reaffirms all the more convincingly the dualism of the mental and the physical. My rebuttal of this contention will be given in the concluding sections. Suffice it here to suggest that if by "physical" we do not understand a kind, type, part, or aspect of reality, but rather a method, language, or conceptual system, then there is no room for a dualistic opposition of mental and physical events or processes, let alone substances.
Notes 1. I.e., sentences containing proper names or coordinates.
2. Except, of course, for such cases as the traveling and returning twin brothel, which, though strictly implied by the well-confirmed principles of Einstein's theory, has not been susceptible to direct check thus far (because of obvious practical difficulties).