Edward Feser, Stephen Barr, and Jerome M. Adler have tried to formulate theoretical accounts that confute reductive materialism. While I agree with their opposition to materialism or naturalism simpliciter, my disagreement with these thinkers stems from their belief in the rational soul. Objections can be made to hylomorphism (a theory posited by Aristotle and received by the Church in modified form) on the grounds of both reason and Scripture. Let us consider the issue of concept-formation for starters.
I am using "concept" to describe representations that are generated by neural machinery as it interacts with sensory stimuli and decodes information which initially arises from sense experience. Additionally, I deny the existence of objective universals (i.e., supersensible intelligibles) and essential natures as they are usually conceived in Platonic and Aristotelian philosophy; however, I can almost guarantee that the ability to form concepts of concepts (second-order reflection) is not precluded by a Christian materialist account of intellection. Such ideas could merely be reinterpreted especially when the materialistic/physicalistic account is understood in the light of Scripture.
For instance, a Christian physicalist could reflect on what it means for X to be a round square although round squares are logically and factually impossible. We can entertain the term "round square" in the mind via imagination and reason, although it's impossible to produce a mental image of such an object. One could also form the concept of a unicorn purely from sensory experience, reflection, abstraction and mental recombination since we do perceive horses and animals with horns. Or it is possible that the contents of a subject and predicate construction (an abstract structure) might be ontologically posterior to what we encounter through sensory experience (ontic subjects and predicates are sensed each day) and thereby such things could be parasitic and supervene on sensible instances of subjects and predicates witnessed experientially (e.g. houses and white objects).
It must be conceded that our ability to form categorical propositions like "All swans are white" or "No swans are white" is something that only rational creatures can do. But it seems that we don't need souls or intelligible substances to justify this ability. We have been gifted with language, and what makes la langue and la parole possible is the human brain (the neocortex along with Broca's and Wernicke's area). Furthermore, la langue makes abstract categorization possible. We're able to manipulate symbols (concepts) because we are lingual beings. So concept-formation can be explained without recourse to multiplying entities beyond necessity (Entia non sunt multiplicanda praeter necessitatem).