Core Tenets
Anomalous monism is built upon three seemingly contradictory principles, which Davidson argues can be consistently held:
- The Principle of Causal Interaction: At least some mental events causally interact with physical events, and vice versa. For example, a desire (mental event) can cause a bodily movement (physical event), and a sensory input (physical event) can cause a belief (mental event).
- The Principle of the Nomological Character of Causality: Where there is causality, there must be a strict, deterministic law subsuming the events that are causally related. This means that for any two events c and e where c causes e, there must exist a strict natural law such that if c occurs, e must occur.
- The Principle of the Anomaly of the Mental: There are no strict psychophysical laws. That is, there are no strict, deterministic laws that connect mental events (qua mental) with physical events (qua physical) or that allow for the prediction and explanation of mental events solely on the basis of physical properties. Mental predicates, according to Davidson, are not part of a closed, deterministic system like physics.
Reconciliation
Davidson reconciles these three principles by arguing for a "token identity" theory without "type identity."
- Token Identity: Every particular mental event (a "token") is identical with some particular physical event (a "token"). For instance, my particular thought "I am hungry" at a specific moment is identical to a specific neural event occurring in my brain at that same moment. This satisfies the monism aspect, as there is only one kind of substance (physical) and mental events are ultimately physical events.
- Anomalous (No Type Identity): While every mental token is a physical token, mental types (e.g., the general concept of "desire" or "belief") cannot be strictly correlated with physical types. There are no strict psychophysical laws that state, for example, "whenever neural pattern X occurs, the mental state of desire Y occurs." The same mental type might be realized by different physical types in different individuals or even in the same individual at different times. This explains the "anomaly" of the mental – the lack of strict psychophysical laws.
When a mental event causes a physical event (or vice-versa), it does so qua physical event, not qua mental event. The causal relation holds under a strict physical law because the mental event is a physical event. However, there is no strict law connecting the mental description of the cause to the physical description of the effect.
Implications and Criticisms
Implications:
- Non-reductive Physicalism: Anomalous monism is a prominent form of non-reductive physicalism. It maintains that everything is physical (monism), but denies that mental properties or concepts can be reduced to physical properties or concepts in a law-like manner.
- Mental Causation: It aims to preserve mental causation by ensuring that mental events, being physical events, can participate in causal relations governed by strict physical laws.
- Supervenience: Davidson suggests that the mental supervenes on the physical: there can be no change in mental events without some change in physical events, but this supervenience does not imply strict laws.
Criticisms:
- Epiphenomenalism: A common criticism is that anomalous monism renders mental properties epiphenomenal. If mental events cause effects only by virtue of their physical properties, and there are no laws relating mental properties to effects, then it seems the mental properties themselves are causally inert or irrelevant. The "mental" aspect of an event doesn't seem to do any causal work.
- The Problem of "Strict Laws": Critics question Davidson's notion of "strict law" and whether it truly distinguishes psychophysical laws from other non-strict laws in science (e.g., in biology or geology).
- Explanatory Gap: Even if token identity is accepted, the lack of type identity and strict psychophysical laws leaves an "explanatory gap" regarding how mental properties arise from physical properties.
- Nature of Mental Properties: Some argue that Davidson's account doesn't adequately explain what mental properties are if they are not reducible to physical properties yet exist within a physicalist framework.
Despite criticisms, Anomalous Monism remains a highly influential and widely discussed position in the philosophy of mind, profoundly shaping debates on the mind-body problem, mental causation, and the nature of physicalism.