Cartesian materialism, Dennett's version: "there is a crucial finish line or boundary somewhere in the brain, marking a place where the order of arrival equals the order of "presentation" in experience because *what happens there* is what you are conscious of." (107)

Cartesian materialism, our version: for any representation in your brain, for any time T, there is a fact of the matter as to whether that representation is, or is not, a conscious representation at T. That is: there is always a definite time at which a given representation becomes, conscious, and a definite time when it ceases to be. (No commitment to there being a special place.)

The Orwellian hypothesis: First, a representation of a blank screen becomes conscious; after it ceases to be conscious, and becomes a memory representation, it is revised, to be a representation of a screen with a colored dot in the middle.

The Stalinesque hypothesis: Your visual cortex generates a representation of a blank screen, but before it becomes conscious, it is revised, to be a representation of a screen with a colored dot in the middle. it then becomes conscious.

The Argument Against Cartesian Materialism:

1. If cartesian materialism is true, then the Orwellian hypothesis and the Stalinesque hypothesis are distinct hypotheses.
2. The Orwellian and Stalinesque hypotheses are not distinct.
3. Therefore, cartesian materialism is false.

An argument for premise 2:

1. If there is no experiment anyone could do to tell whether it is the Orwellian or the Stalinesque hypothesis which is true, then the hypotheses are not distinct.
2. There is no experiment anyone could do to tell whether it is the Orwellian or the Stalinesque hypothesis which is true.
   "One posits a Stalinesque "filling in" on the upward, pre-experiential path, and the other posits an Orwellian "memory revision" on the downward, post-experiential path, and both of them are consistent with whatever the subject says or thinks or remembers" (123).
3. Therefore, the hypotheses are not distinct. "There is really only a verbal difference between the two theories" (125).

Experiment 1: measure the time from stimulus to consciousness. If it is shorter than the gap between the two flashes, then the Stalinesque hypothesis is false.

Experiment 2 (actually performed): measure the time from stimulus to consciousness of a red flash when (i) a red flash is presented alone, and when (ii) a red spot is presented followed, after a 200msec delay, by a green spot in a different pace.

Outcome: there was no different in the measured times.

What does this show? If the Stalinesque hypothesis is true, then there should be a delay in case (ii) that is absent in case (i).

Dennett's replies...

Question: what alternative to Cartesian materialism is there?