Dualism Notes

Dualism in Philosophy of Mind

Dualism posits that within a specific domain, there exist two fundamentally distinct kinds or categories of entities or principles. It is contrasted with monism, which posits a single fundamental kind, and pluralism, which posits multiple kinds.

In the philosophy of mind, dualism is the theory that the mental and the physical are radically different. Given the common-sense acceptance of physical bodies, materialist monism is often considered the default position. Thus, discussions of dualism usually begin by assuming the reality of the physical world.

1. The Mind-Body Problem and the History of Dualism

1.1 The Mind-Body Problem

The mind-body problem explores the relationship between mental and physical properties. Humans seem to possess both:

  • Physical properties: size, weight, shape, color, motion through space and time, etc.
  • Mental properties: consciousness, intentionality, and a subjective self.

Physical properties are public, observable in principle by anyone, even if through scientific techniques. Mental properties, particularly conscious experiences, are private and accessible directly only to the subject.

The mind-body problem includes several key questions:

  1. Ontological question: What are mental and physical states? Is one a subclass of the other, or are they entirely distinct?
  2. Causal question: Do physical states influence mental states and vice versa? If so, how?
  3. The problem of consciousness: What is consciousness, and how is it related to the brain and body?
  4. The problem of intentionality: What is intentionality, and how is it related to the brain and body?
  5. The problem of the self: What is the self, and how is it related to the brain and body?
  6. The problem of embodiment: How is the mind housed in the body? How does a body belong to a particular subject?

Philosophical views addressing these problems include:

  • Materialism: Mental states are physical states.
  • Idealism: Physical states are mental.
  • Dualism: Mental and physical are both real and distinct.
1.2 History of Dualism

The focus of dualism has shifted over time:

  • Classical and medieval periods emphasized the intellect.
  • Later, consciousness became the main focus.

Plato:

  • Believed true substances are eternal Forms, not ephemeral physical bodies.
  • Forms enable intelligibility.
  • Intellect is immaterial and has an affinity with Forms, striving to leave the body and dwell in the realm of Forms.
  • Problem: The connection between a particular soul and body lacks clear explanation.

Aristotle:

  • Forms exist embodied in things.
  • Soul is the form of the body, explaining the union of body and soul.
  • The intellect differs from other faculties by not having a bodily organ.
  • Argument: Intellect must be immaterial to receive all forms, as a physical organ would restrict its sensitivity.

Aquinas:

  • Identifies soul, intellect, and form as substance.
  • Immaterial soul is the substance of the human person but not the person itself until united with the body.

Descartes:

  • Substance dualist: two kinds of substance – matter (spatially extended) and mind (thinking).
  • Bodies are machines operating by their own laws.
  • Minds influence bodies by interacting with the machinery.
  • Pineal gland as the location of interaction.
  • Challenge: How can thought and extension interact?

Empiricists:

  • Locke: Accepted material and immaterial substances.
  • Berkeley: Rejected material substance; initially considered rejecting immaterial substance but concluded the self is essential.
  • Hume: Rejected the self; proposed bundle dualism – the mind is a bundle of impressions and ideas without an owner.

Mechanism in the 19th Century:

  • The world is closed under physics, leaving no scope for mental interference.
  • Conscious mind as an epiphenomenon.
  • Rise of materialist monism to avoid counterintuitive implications.
  • Revival of property dualism more recently.

2. Varieties of Dualism: Ontology

Classified by what is considered dualistic:

  • Predicate dualism
  • Property dualism
  • Substance dualism
2.1 Predicate Dualism

Psychological predicates are essential for a full description of the world and are not reducible to physicalistic predicates. Reduction requires bridging laws connecting psychological states to physical states, without loss of information. Psychological predicates are irreducible due to multiple realizability and functional definitions.

2.2 Property Dualism

Property dualism asserts that there are two essentially different kinds of properties. Even if individual instances are physically constituted, the ontology of physics is insufficient. Irreducible language requires something more than the initial physical ontology.

2.3 Substance Dualism

A substance is more than the collection of its properties; it is that which possesses them. Mental states and the subject that possesses them are immaterial. Hume considered minds to be bundles of immaterial states. Substance dualism is also referred to as Cartesian dualism.

3. Varieties of Dualism: Interaction

If mind and body are different realms, how are they related?

3.1 Interactionism

Mind and body causally influence each other, a common-sense belief.

Challenges:

  • Objection based on the radical difference in kinds between mental and physical.
  • Conflict with the conservation of energy. Responses involve considering the body not as an isolated system or the mind influencing the distribution of energy without altering its quantity.
  • Overdetermination: both physical and mental causes for behavior. Relies on the possibility of causal overdetermination.
  • Quantum Indeterminacy: physical laws might be indeterministic, making mental influence consistent with the laws.
3.2 Epiphenomenalism

Mental events are caused by physical events but have no causal influence on the physical. It primarily preserves the autonomy of the physical.

Problems:

  • Counterintuitive.
  • No evolutionary reason for mental states.
  • Challenges the rationality of belief in epiphenomenalism and the argument from analogy for other minds.
3.3 Parallelism

Denies all causal interaction between mind and body. Requires belief in a pre-established harmony, often by God.

4. Arguments for Dualism

4.1 The Knowledge Argument Against Physicalism

Based on the existence of qualia. If a scientist (Harpo) learns something new upon experiencing a sensory modality for the first time, after knowing all the physical facts, then qualia are non-physical.

Responses:

  • Harpo acquires knowledge how, not factual knowledge.
  • New knowledge is a new way of grasping something already known through demonstrative concepts.
4.2 The Argument from Predicate Dualism to Property Dualism

The irreducible special sciences are not wholly objective but depend on interest-relative perspectives, which in turn depend on minds and mental states.

4.3 The Modal Argument
  1. It is imaginable that one’s mind might exist without one’s body.
  2. It is conceivable that one’s mind might exist without one’s body.
  3. It is possible one’s mind might exist without one’s body.
  4. One’s mind is a different entity from one’s body.

This argument relies on the move from imaginability to real possibility.

4.4 From Property Dualism to Substance Dualism

This section focuses on discontent with property dualism, particularly in its Humean form. Hume’s “bundle” theory suggests mental states exist without a subject or substance possessing them.

4.5 Arguments from Personal Identity

The identity of persons over time is not conventional in the way the identity of other substances is.

4.6 The Aristotelian Argument in a Modern Form

Aristotle’s argument concerns the limitations matter places on the range and flexibility of human thought.

Modern concerns:

  • Cognitive phenomenology: Belief that thoughts are conscious.
  • Physical systems operate by physical laws not meanings.
  • Frame Problem: “Mechanical mind” lacks common sense.
  • Benacerraf’s Problem: How does a physical brain interact with abstract entities?

5. Problems for Dualism

5.1 The Queerness of the Mental

Mental states are characterized by subjectivity and intentionality, which are difficult to reconcile with a purely physical understanding.

5.2 The Unity of the Mind

Explaining the nature of the unity of the immaterial mind poses challenges for both bundle theorists and substance dualists.

5.2.1 Unity and Bundle Dualism

Bundle theory needs an account of what constitutes the unity of the mind, usually through a primitive relation of co-consciousness.

5.2.2 Unity and Substance Dualism

Explaining what an immaterial substance is such that it explains the unity of the mind. Approaches include:

  • ‘Ectoplasm’ account: Immaterial substance is like immaterial stuff.
  • ‘Consciousness’ account: Consciousness is the substance.
  • ‘No-analysis’ account: It's a mistake to present any analysis.