Mortimer J. Adler : biography
Adler was a self-proclaimed “moderate dualist”, and viewed the positions of psychophysical dualism and materialistic monism to be opposite sides of two extremes. Regarding dualism, he dismissed the extreme form of dualism that stemmed from such philosophers as Plato (body and soul) and Descartes (mind and matter):
Adler also disagreed with the theory of extreme monism. He believed that while mind and brain may be existentially inseparable, and so regarded as one and the same thing, the mental and the physical may still be analytically distinct aspects of it. He put this theory to the test in the following manner:
Adler was also a harsh critic of the Mind-Brain Identity Theory:
After eliminating the extremes, Adler subscribed to a more moderate form of dualism. He believed that the brain is only a necessary, but not a sufficient, condition for conceptual thought; that an immaterial intellect is also requisite as a condition; and that the difference between human and animal behavior is a radical difference in kind. His reason for this is that their cognitive sensory powers do not and cannot apprehend universals. Their cognitive reach does not go beyond particulars. Hence, we would not be able to apprehend universals if we did not have another and quite distinct cognitive power – the power of intellect. Our concepts are universal in their signification of objects that are kinds or classes of things rather than individuals that are particular instances of these classes or kinds. Since they have universality, they cannot exist physically or be embodied in matter. But concepts do exist in our minds. They are there as acts of our intellectual power. Hence that power must be an immaterial power, not one embodied in a material organ such as the brain.
Adler argued that if such an immaterial power did not exist in human beings, our use of common nouns would not be possible. Particular instances are designated by proper names or definite descriptions. When we use the word "dog," we are referring to any dog, regardless of breed, size, shape, or color. To refer to a particular instance, we would use a canine name, such as "Fido," or a definite description, such as "that white poodle over there lying in front of the fire." Our concepts of dog and poodle not only enable us to think about two classes of animals, they also enable us to understand what it is like to be a dog or a poodle.
According to Adler, The action of the brain, therefore, cannot be the sufficient condition of conceptual thought, though it may still be a necessary condition thereof, insofar as the exercise of our power of conceptual thought depends on the exercise of our powers of perception, memory, and imagination, which are corporeal powers embodied in our sense-organs and brain.
Only if the brain is not the sufficient condition for intellectual activity and conceptual thought (only if the intellect that is part of the human mind and is not found in other animals is the immaterial factor that must be added to the brain in order to provide conditions both necessary and sufficient) are we justified in concluding that the manifest difference in kind between human and animal minds, and between human and animal behavior, is radical, not superficial. It cannot be explained away by any difference in the physical constitution of human beings and other animals that is a difference in degree.
Adler defended this position against many challenges to dualistic theories. For example, David Hume believed that man is equipped with sensitive faculties only, and has no intellect. As a nominalist, Hume then faced the problem of how to explain the meaning of the general words in our everyday language; for example, the common nouns that signify classes or kinds. Hume attempted to solve this problem by arguing that when we use words that appear to have general significance, we are applying them to a number of perceived individuals indifferently; that is, without any difference in the meaning of the word thus applied.