By: Anthony Aubel
Dualism, in general, is a position that claims there are two fundamental kinds, or radically different, categories of things or principles. In philosophy of mind, dualistic claims arise in the context of the mind-body (or brain) problem. Intuitively, we find our experiences, beliefs, and other sensations that we identify as mental to be different than physical entities. At its basis, it is this intuitive sense that has paved the way for us to differentiate the mental phenomena from the physical world and prompted questions about dualism. Yet this apparent intuition finds itself in conflict with scientific, or physicalist, standpoint which generally claims all that exists is physical. Therefore, physicalists generally do not see mental phenomena as distinct from physical. These polar views give rise to basic questions: what is the then relationship (if any) of mind and body? Are there two distinct entities in contrast to just one, as in monism? Do they have different properties? In this paper, I will attempt to defend a form of dualism position that may be reasonable to hold.
From an ontological perspective, there are two main types of dualism: 'substance' and 'property' dualism. Substance dualists, such as Descartes, argue that the mind and the body are composed of different substances and that the mind is identified as a distinct substance that thinks while lacking physical attributes such as size, shape, and location. For property dualists, on the other hand, mental phenomena, or states, are non-physical properties of physical substances that cannot be reduced to brain states.
Physicalists generally agree that there is only one kind of substance in the world and that it is physical in nature. Empirically, science has not found any evidence for non-physical substances. Therefore, physicalists view substance dualism as implausible. They view the mind, or mental states, as identical, or reducible to, the physical. This is consistent with laws of causal closure that claims every physical event has a sufficient physical cause. Dualistic claims seem to be in conflict with such causal closure principles. By pointing to the presence of non-physical entities outside the physical realm, dualists face the challenge of explaining how there can be any interaction between the physical and the non-physical. This is one of the primary reasons why dualism is a difficult position to hold.
Property dualism does not seem to fare any better either. Although, it can be a more plausible claim than substance dualism and may seem to be more compatible with physicalist position in virtue of affirming the existence of only one substance having both physical and mental properties, it nevertheless fails to explain how the two can possibly interact. In addition, physicalist's notion of property dualism assumes that all mental properties are ultimately reducible to the physical. But by reducing the mental to the physical, the physicalists fail to account for the phenomenal character of our experience; the subjective character of mental states, or what is referred to as qualia. More notably, attempts to reduce properties to physical need not then be restricted to persons. This can then lead to more implausible theories, such as panpsychism, that claim all things can have mental properties. As such, a dualist need not commit to such reduction. A reasonable dualist position, therefore, will need to provide an account for the interaction challenge without committing to reduction. So how could this come about?
One possibility is to re-consider how we view the dual entities in question. More specifically, It is possible to consider the mind, or mental states, and the physical brain as two different modes of the same underlying structure; The mental and the physical are seen as different aspects of the same thing. Brain states can be viewed as those states that manifest in observable physical form and mental states are those that manifest in the form of experience, yet the two modes are grounded firmly on one underlying structure without either having to reduce to the other. It is true that, in principle, this view would be monistic, but it emphasizes dual modes and as such, it may provide reasonable grounds for addressing some of the challenges faced in substance and property dualism.
In philosophic literature, this position is formally known as 'dual-aspect', or DM (for dual-mode) monism which attempts to find a middle ground to accommodate for both the physical and the mental. The classic example is presented in Baruch Spinoza's Ethics. In part two of the Ethics, he maintains "The human mind and the human body are two different expressions—under thought and under extension—of one and the same thing: the person. And because there is no causal interaction between the mind and the body, the so-called mind-body problem does not, technically speaking, arise." (Nadler 22). This is in contrast to Descartes's substance dualism, which suffers from the problem of how two radically different substances unite to cause effects in each other. Spinoza disagrees with Descartes about the essence of the mind and the body; he denies that the human being is a union of two substances.
In particular, "he's [Spinoza] suggesting that the mind and the body are unified in one of the strongest senses, in that they’re identical, while also insisting that there is a fundamental difference between thought and motion, so fundamental that minds can’t instantiate motion and bodies can’t instantiate thought."(Morrison 3). In principle, this way of thinking echos what contemporary DM monism holds as its central thesis with respect to the dual nature of entities in question.
Similar views, although expressed somewhat differently but pointing to the same idea, can also be found to support a DM monism. For example, David Chalmers, in one of his more seminal works "Consciousness and its place in nature" states: "monism promises a deeply integrated and elegant view of nature. Few detailed theories in this class have been developed, and it is not yet clear whether such a view can be developed in a way that simultaneously accommodates all the data of physics and phenomenology. But at the same time, there appear to be no strong reasons to reject the view. As such, [...] monism is likely to provide fertile grounds for further investigation, and it may ultimately provide the best integration of the physical and the phenomenal within the natural world." (Chalmers and others 11). This expresses a form of monism that simultaneously seems to account for dual aspects of the physical and the mental phenomenon.
But how does DM monism address the dualist challenges? To see how this may be, we can think of there existing one entity without having to embrace a physicalist reduction. From a DM monist perspective, events are not overdetermined by either the physical or the mental. There exists only one entity, but one does not take any priority over another; The mind can persist without the need of being reduced to the physical brain. As Jiri Benovsky elegantly puts it "Events only have one metaphysical kind of causes: causes that are both physical and mental or 'phental' (Benovsky 8). This concept is used to highlight what is meant by a 'mode' or an 'aspect' while differentiating it from 'property'. Unlike properties, modes are viewed as fundamental and irreducible to each other. A mode is not exemplified by an entity, such as a person, like a property is. For the DM monist, the person is not physical, it is not mental, it's dual.
DM monism, therefore, allows dualist to be compatible with physicalist view without one resorting to any kind of priority over another. As a result, there are no absolute physical world to which mental is reduced to. In essence, DM monism claims there is only one entity which has two aspects, a mental and a physical, presented equally and non-reductively.
With respect to the problem of interaction, DM monism explains mental and physical events as two aspects of one and the same thing. We can once again consider the classic example of 'pain' (mental) and 'C-fibers firing (CFF)' (physical) events to see how it would fit under DM monist position. When we feel the sensation of pain, the experience is one of the ways, the 'mental' way in this case, that becomes accessible to us. If we were able to experimentally measure certain changes in the brain, say in the form of signals present while experiencing the pain, then that would be the second way, the 'physical' way, that the information becomes accessible to us. But for the DM monist, these are just two aspects of one and the same thing; namely, 'pain'. Therefore, we seem to have access to two things, the feeling of pain and the experimental observation, while both being two aspects of one and the same thing. So for the dualist, interaction can be explained in terms of detecting and interacting with one thing (i.e. pain) in two different ways.
Although DM monism may seem to provide an elegant way to deal with challenges posed for dualism, it does have its own shortcomings. For instance, although we have discussed how a mode differs from a property, questions still remain as to what exactly the nature of a mode is or what we mean by a mode. In addition, DM monism seem to be pointing to an underlying structure. Exactly what could be the nature of such an underlying structure is an open question. While such questions are at the center of lively debates in contemporary philosophy of mind, DM monism seem to provide reasonable grounds for further development of a dualistic theory.
References:
Benovsky, Jiri. “Dual-Aspect Monism.” Philosophical investigations, vol. 39, no. 4, 2016, pp. 335–52.
Chalmers, David J, and Others. “Consciousness and its place in nature.” Blackwell guide to the philosophy of mind, 2003, pp. 102–42.
Forrest, Peter. “The Identity of Indiscernibles.” The Stanford Encyclopedia of Philosophy, edited by Edward N. Zalta, Winter 2020, 2020, https://plato.stanford.edu/archives/win2020/entries/identity-indiscernible/.
Morrison, John. “Spinoza on mind, body, and numerical identity.” Unpublished manuscript, 2016.
Nadler, Steven. “Baruch Spinoza.” The Stanford Encyclopedia of Philosophy, Summer 2020 Edition, 2020, https://plato.stanford.edu/archives/sum2020/entries/spinoza/.