  As remarked above, Place preferred to express the theory by the notion of constitution, whereas Smart preferred to make prominent the notion of identity as it occurs in the axioms of identity in logic. So Smart had to say that if sensation X is identical to brain process Y then if Y is between my ears and is straight or circular (absurdly to oversimplify) then the sensation X is between my ears and is straight or circular. Of course it is not presented to us as such in experience. Perhaps only the neuroscientist could know that it is straight or circular. The professor of anatomy might be identical with the dean of the medical school. A visitor might know that the professor hiccups in lectures but not know that the dean hiccups in lectures.