I’d like to try out this small argument for substance dualism. Let a quasi-miracle be a sequence of events that is both (i) remarkable and (ii) extremely improbable. Flipping a fair coin 1,000,000 times and its landing heads 1,000,000 constitutes a quasi-miracle. A chimpanzee at a typewriter producing a 950-page dissertation on anti-realism is another quasi-miracle.
Our world is indeterministic, and improbable events occur often. But quasi-miracles do not occur, and certainly do not occur regularly. Suppose you perform some action A and claim that A was done freely. For instance, let A be some deliberate and serious action such as swearing to tell the truth. Now suppose you are asked whether you did in fact act freely in swearing to tell the truth. You answer yes, or you type Y on your computer. I ask you again whether you acted freely in swearing to tell the truth, and again you type Y.
Since our world is indeterministic, there is always some small chance that any physical event fails to occur. But I claim that no matter how many times you were asked whether the action A was done freely, you would answer Yes. The resulting sequence of physical events would be both remarkable and extremely improbable. It would take the form Y,Y,Y,Y,Y,Y,Y,Y ….. oo. So if every instance of your answering Yes was nothing more than a physical event, there would be lots of quasi-miracles occurring, or we could easily make lots of quasi-miracles occur. But, by definition, we cannot make lots of quasi-miracles occur. Therefore, it is false that every instance of your answering Yes is purely a physical event. But this is just to say that some non-physical events occur. But then dualism is true.
Here’s another way to put the argument.
1. Indeterminism is true. Fact
2. Quasi-miracles do not occur (or almost never occur). Fact
3. For each agent S and free action A, S can affirm indefinitely that S performed A freely. Fact
4. If physicalism is true, then for each agent S and free action A, S can bring about a quasi-miracle.(from 3 and Def. quasi-miracle).
5. Physicalism is not true. From 2,4.
6. :. Dualism is true. From 5, and reasonable assumptions about idealism.