The Mind Body Problem Our minds seem to be non-physical and different from our bodies. Our bodies seem to be something different from our minds. Are they actually different? What is a mind? What is a body? How do they relate?

Substance Dualism Our bodies and minds are separate things Substance – a “thing” which exists independently from other things (e.g. a horse, a cat, a human). It has properties, but is not a property of another thing Property – a quality that a substance has (e.g. red, round, cold) Substance: Socrates Balding head Grey Hair

Descartes Meditations Meditation 1 – I can’t be sure that I have a body, that other people, or my past or the world outside my head really exists. I could be tricked Meditation 2 – But, I cannot doubt that I exist because I am thinking about myself. I am a permanent self- contained, self-conscious ego B 1596 D 1650 Meditations 1641

Argument for Substance Dualism The Conceivability argument (Descartes): P1: I can doubt that my body exists (from Meditation 1) P2: I cannot doubt that my mind exists (from Meditation 2) P3: If A differs in any way from B, then A is not B --------------------------------------------------------- C: So, my mind is not my body

Analogy to the Conceivability Argument P1: I can doubt that I’m drinking H20 P2: I cannot doubt that I’m drinking water P3: If A differs in any way from B, then A is not B -------------------------------------------------------- C: So, Water is not H20

Descartes’ Divisibility Argument P1: My body is divisible P2: My mind is not divisible P3: If A differs in any way from b, A is not B ----------------------------------------------------- C: So, my mind is not my body

Princess Elizabeth’s Objection to Descartes How can a totally non-physical mind cause things to happen to a totally physical body? How can a totally physical body cause things to happen to a totally non-physical mind?

The “Life after Death” argument P1: If substance dualism is false, then my mind cannot exist independently from my body P2: My mind can exist independently from my body (NDEs, ghosts, reincarnation, etc) ---------------------------------------------------------------- C: So, Substance dualism is true

Physicalism The mind is the brain itself and nothing more. In other words, mind = brain

Argument for Physicalism Neuroscience has shown a strong link between what happens to and in our brains and what happens to and in our minds Argument for Physicalism

The Case of Phineas Gage

Against Physicalism A complete physical description of our brains and bodies, even in every detail, still seems to leave out something. What is left out is our personal/subjective experience, the “what it's like for us.”

The Case of Mary

Inverted Spectrum Case

Property Dualism vs. Substance Dualism Mind is not Body Mind can exist apart from body; in other words, mind & body are independent substances Property Dualism: Not all mental states are physical states Mind cannot exist apart from body; in other words mind & body are two aspects of ONE AND SAME substance