The Princess Elizabeth Argument

Materialism: Human beings are wholly material—every part of a person, including the mind, is a material body.Dualism: Human beings are not wholly material—the body is material, but the mind is immaterial.

Interactionism: Minds and bodies enter into direct, two-way causal interactions.Cartesian Dualism=Dualism+Interactionism

For it seems that all determination of movement takes place by the propulsion of the thing moved, by the manner in which it is propelled by that which moves it, and by the qualification and shape of the surface of this latter.  Contact is required for the first two conditions, and… touching seems to me incompatible with an immaterial thing.

Elizabeth’s Principle: Causation requires contact.

The Princess Elizabeth Argument

1) If Interactionism is true, the mind moves the body.

2) If the mind moves the body, it contacts the body.

3) If the mind contacts the body, it occupies space.

4) If the mind occupies space, it’s material.5) If the mind is material, then Dualism is false.6) If Interactionism is true, then Dualism is

false.

For example, on the supposition that gravity is a real quality, about which we know no more than its power of moving the body in which it occurs towards the centre of the Earth, we find no difficulty in conceiving how it moves the body or how it is united to it; and we do not think of this as taking place by means of real mutual contact between two surfaces…

Newton’s First Law: Objects at rest stay at rest unless acted upon by an outside force.Newton’s Second Law: F=ma.

The Newtonian Argument

1) If Interactionism is true, the mind moves the body.

2) If the mind moves the body, it exerts a force.

3) If the mind exerts a force, it has mass. 4) If the mind has mass, it’s material.5) If the mind is material, then Dualism is

false.6) If Interactionism is true, then Dualism is

false.