Once during a philosophy oral examination, some professors asked me to defend my “controversial” contention that philosophical materialism was not rationally defensible. I answered that Aristotle’s simple refutation of the materialist account of mind is sufficient, but I do not think that proofs end there. Aristotle points out that the mind must be at least partially immaterial for it to be able to contemplate so many different objects, including immaterial objects. Moreover, one cannot deny that there are immaterial objects of the mind because the mind thinks about the structure and objects of mathematics, which are most definitely not material.
The Platonic objection to materialism may be even stronger. If materialism wishes to reduce all reality to constituent material parts, such as atoms or the misnamed subatomic particles, it must attribute the structure of reality in all its diversity and apparent order to the structure of those constituent parts individually and in combination. Yet, the materialist cannot reduce the structure of the parts themselves and the structure of their combinations to the parts themselves. The structure is immaterial. The form of each material part itself is not material. However, if a materialist objected and said that we cannot get “behind” the basic fact of the smallest constituent material part—that it is simply what it is, structure and matter together, then he still could not explain any reality beyond the mere facthood of each radically unique indivisible material part. Yet, we know that these constituent parts are not radically unique; they have particular structures that they share with other constituent parts. There are classes of subatomic particles, and there are types of atoms. A structure—an order—that is shared cannot itself be material. This same problem for materialism applies to all higher material combinations. Any given molecule has a certain structure that itself is not material.
Therefore, materialism is rather idiotic. Intelligent people often adopt it, but unthinkingly; they never ask metaphysical questions, though they affirm a metaphysical theory. I really do not understand why this occurs, especially among physicists who ought to be more demanding of their assumptions. I guess that most of these folks are simply interested in physical phenomena; they do not wish to trouble themselves with underlying metaphysical principles.