Advantages of Hylomorphism over Modern Substance Dualism

What are the advantages of hylomorphism over modern substance dualism?

1. Ethical. Hylomorphists can explain the unique and intrinsic evil of such acts rape and torture. For dualists, these acts are evil only either of two ways: as an unjust destruction or use of someone else’s property, or as causing some kind of mental suffering or distress. But this surely understates and misdescribes the evil involved. These acts have a special kind of evil because they are violations of the human person itself, in its bodily incarnation.
   
2. Epistemological. Here I can rely on a form of direct realism about sense perception. For hylomorphists, sense perception involves a unified causal process linking the object with the perceiver. The sensed object is the agent of this process, and in Aristotelian natural philosophy, the agent is ontologically inseparable from the subsequent process. The process is ontologically dependent on the agent. Hence, the perceiver is connected at deep ontological level to the object of perception. For dualists, there are two distinct causal processes involved: one linking the remote object to the brain, and a second connecting the brain to the soul. It seems that the dualist can allow only for direct perception of brain states. Remote objects could only be perceived via representations of them in the brain. If dualists suppose that the living body and not the soul is the primary subject of sense perception, then they will confront the problem of how we are able to combine sensory knowledge with rational knowledge.  Consequently, an Aristotelian account of direct realism is unavailable to the dualist, and I don’t know of any viable alternative.
3. The Chain of Being and the proliferation of souls. Since dualists need souls to account for consciousness, they must either posit a soul for every sentient organism or else embrace Descartes’ bizarre denial of real sentience to non-human animals. But sentience seems very widespread in the biological domain: even plants and one-celled organisms seem capable of sense perception. Do we feel comfortable positing substantial souls for every sentient being? Many of the billions of cells making up my body display a degree of sentience—are there billions of souls attached to each human being?

At very low levels in the Chain of Being, like the souls of sponges or amoebas, the soul seems to be doing no explanatory work. The soul of an amoeba would seem to be epiphenomenal and causally inert. How would a soulless amoeba function differently?

Admittedly, hylomorphists posit an even greater number of souls and substantial forms in the world. Even inorganic substances need substantial forms. However, these substantial forms do much more work than merely grounding the possibility of consciousness. They are the ultimate source of a substance’s active and passive causal powers, and of its internal organization.

4. Accounting for living bodies and the pairing problem. The task of explaining the persistence of living organic bodies, animals, plants, and micro-organisms, is a problem for everyone, hylomorphists and dualists alike. Dualists need living bodies to persist through mereological change in order to solve the pairing problem. Souls are not attached to individual micro-particles or a particular swarm of micro-particles, but rather to a persisting living body. Unlike hylomorphists, dualists cannot appeal to the soul as the ground for the persistence of the living body, since doing so would make their answer to the pairing problem viciously circular. So, they would have to resort to some sort of physicalistic explanation, but no such explanation is in fact viable. From the physicalist point of view, living organisms are merely “emergent” phenomena in the Dennettian sense, and the criteria for synchronic unity and diachronic persistence are at least partly conventional or stipulative. Any laws connecting souls with congeries of particles would be extremely complex and ugly.

5. Explaining the functional dependence of the soul (even in its most intrinsic and characteristic activities) on the integrity of the material brain. For Thomists, the rational soul is the also the form of the organic body, and its characteristic activities, including occurrent thoughts and processes of reasoning, necessarily involve the functioning of material organs. Where immaterial enters the story for the Thomist is in accounting for the relation of understanding that holds between a rational soul and certain universals, a relation that is brought about as the result of the action of a purely immaterial faculty of abstraction. However, making particular judgments and engaging in a succession of inferences always involves the manipulation of ‘phantasms’, sensory-like images whose generation is a function of relevant parts of the brain.

Since the traditional dualist thinks of the soul as a separate substance, there is no reason to expect the internal activities of the soul to depend in any way on the condition of parts of the body. God could certainly establish such dependencies in an ad hoc way, for purposes beyond our ken. So, this objection is not apodeictic but rather Bayesian in character. For dualists, these cases of mind/brain dependency are antecedently surprising in a way that they are not for hylomorphists.