1. Recap: What is multiple realisability? Why is it an issue for MBTIT?

2. Multiple Realisability – Why is it an issue?
The issue for Bob the alien, a dog and the man with the damaged brain is that according to MBTIT mental processes just are referring to specific brain processes. Therefore if a being or creature does not have those specific brain processes, how can they ever have the associated mental processes? Brain Process A ====== > Mental Process A Brain Process B ====== > Mental Process B Without Brain process A or B you cannot have Mental Process A or B. If there can be different physical states who share the same mental state, then MBTIT is wrong.

3. A Weak Response
A possible response from the MBTIT is to say that in all of these examples the creatures / people involved are having mental states but they are subtly different, enough that if we were being specific we would describe them as “alien pain”, “dog pain” or, rather disturbingly, “man with half a brain pain”. But this is not generally considered to be an effective response. Pain is pain because of how it feels to the agent involved and we would imagine a broken bone in an animal would feel the same as a human with a broken bone etc. We seem to have the same thought / feeling despite our physiology, not because of it.

4. A Secondary Issue
If we focus for the moment on the response of “different types of pain” ( dog pain, bird pain, human pain etc.) then we encounter a second issue – there are now as many different types of pain as there are different brains. At this point what, if anything, makes each of these things pain? What do they have in common if not specific brain states? Why define them as such? If it is simply because the agent is acting as if they are in pain, then we are moving subtly away from MBTIT and towards a behaviourist approach – that mental states are simply expressions of behaviour.

5. Summary Tasks:
Complete the summary sheet for MBTIT – for each criticism be careful to explain why it is an issue for the theory.
Revise your notes ready for a short test in the second part of the lesson. This will only be on MBTIT.

6. MBTIT Test
What is meant by the term ontologically reducible? (3 marks)
What claim do Mind-Brain Type Identity Theorists make about mental states? (3 marks)
Outline the problem of multiple realisability against MBTIT (5 marks)
Outline the location problem against MBTIT (5 marks)
Plan a 25 mark answer: “The mind is ontologically reducible to the brain”