1. Recap Questions What is interactionism?
What is the A Priori problem of interaction?
How does Descartes respond to the problem?
What is the Empirical problem of interaction?
Is it possible to answer this criticism?

2. The A Priori Problem of Interaction
One problem for Descartes (and indeed any version of dualism) when it comes to interactionism is their apparent inability to explain how a non-physical mind can causally interact with a physical body.
Usually for two things to interact they must share at least one of the same properties (extension in space being the primary one). The mind and body do not have this similarity.

3. The Empirical Problem of Interaction
Our bodies and the universe work in the same way as this car. They are closed systems. There is no room for a non-physical causal interaction.

4. Chalmers Response
Mental properties and physical actions (remember property dualist!) have a fundamental relationship. That is to say, we can’t really give an account of how the mental causes particular events in the physical we just know it does (ala David Hume). Whilst this may seem weird it’s the same for any fundamental causal relationship – we don’t really know for sure how gravity works for example. It’s just a part of the universe we have to accept.

5. But what if Interactionism fails…
What might the relationship between the mind and body be? Any ideas?

6. Correlation Not Causation
One reaction to the problem of mental causation that substance dualists may pursue is to accept that there is no causal reaction between the mind and body, but simply a correlation between states of mind and of the body.
Malebranche (a follower of Descartes) formulated a version of this idea known as occasionalism.
He was convinced that the mind and body were two different substances, but also accepted the problem of interactionism we highlighted last lesson.

7. Occasionalism
His view is radical (and is generally considered rather odd). The appearance of interaction is in fact an illusion. Certainly events in the physical body are associated with mental events but they are not causally related. My physical states do not cause mental states and vice versa. How then does this relationship work? Is it just a coincidence that they seem to happen at the same time? Nope!

8. Occasionalism
For Malebranche it is God who organises things such that events in the mental and physical universes coincide in the law-like way that they do. His argument for this involves the claim that only God can be a genuine causal agent – he is effectively the halfway house between our mental states and physical states. Any obvious issues here?

9. Pre-Established Harmony
Leibniz was also persuaded by the idea of Substance Dualism, however he accepted that God constantly intervening to cause mental / physical events for each person seemed a little ridiculous. Instead, he argued, when God created the Universe he created each substance so that it would unfurl under it’s own dynamic in such a way that events in one would correspond with events in the other.

10. Pre-Established Harmony
Can you think of any objections to these ideas? What does it mean for our decision making at any given point? Do these theories assume anything?

11. Quick Questions What is Malebranche's occasionalism?
Are there any major issues with this idea?
What is Leibniz’ Pre-Established harmony?
What does it mean for human free-will?

12. A Better View: Epiphenomenalism
Quick summary of Property Dualism – Go!

13. A Better View: Epiphenomenalism
If we follow property dualism and accept that minds are irreducible to the physical, and they simply emerged from physical matter becoming sufficiently complex it seems that the universe only runs on physical causes (this seems to be supported by science). If this is true we are led to the idea that the mind is a product of the brain, but the it is has no causal influence on the body and its actions at all. It sits above the brain but does not change it.
Read through the history of this idea and note down the key arguments - Page 269 of the textbook.

15. Epiphenomenalism
Theory offered by T.H. Huxley ( ) A major supported of Darwin’s theory of evolution.
Identified reactions in animals and humans that seemed to have no link to mental causes or interventions.
Argued that since our bodies can react without the input of our mental states, there is no reason to suppose that our mental states causally interact with our bodies at all.
Conscious experiences are merely a by-product of physical actions and causes.

16. A Better View: Epiphenomenalism
In other words, if property dualists accept the causal closure of the physical, then mental states may be produced by physical brains, but they cannot have any reciprocal influence on bodies. This view is known as epiphenomenalism. It is usually associated with the idea that the mental states sit “above” the physical, known as supervenience.
“Volition” concludes Huxley, “is an emotion indicative of physical changes, not a cause of such changes.”

17. Reason put simply…
If the knowledge and zombie arguments work, then property dualism is true. On the other hand, the claims that physical laws govern all events in space-time and that every event has a physical cause seem appealing due to modern scientific breakthroughs. Epiphenomenalism allows both ideas to be true. We have non-physical minds, but they are causally inert. They are caused but don’t cause anything themselves.

18. Considering Epiphenomenalism
Summarise a basic view of Epiphenomenalism for your notes.
What major problem of interactionism does it avoid?
Consider the following questions, do they suggest some problems for Epiphenomenalism? (Whiteboards!):
Do you have any good reasons for supposing your volitions (mental states) really cause your actions?
Do you have any good reasons for supposing your sense experiences cause behaviour? (e.g. pain causing you to flinch)
What of conscious perception? Is there a good reason to suppose your visual perception of tea is causally involved in you reaching for it?
Consider other mental states such as beliefs. In what ways do they seem to be physically related to the world? Do you have any reason to suppose they really are so related?

19. Research and write out 3 criticisms of Epiphenomenalism.
Homework
Research and write out 3 criticisms of Epiphenomenalism.
You will be expected to share at least one of them next lesson so make sure you are clear on what they mean.
For each criticism identify clearly why it is a criticism and whether you think it is effective.
Ensure you have 3 to avoid repeating what other people have said.
Do not just copy and paste from the internet, this doesn’t demonstrate understanding, only laziness.
Due next lesson.