I just had a rather long exchange on Twitter with Truth (T) and The Thinker (TT) on the topic of mind, dualism, and reductionism. In the exchange I focused on making a simple but important point: when one types a tweet one brings about an event in the material world (i.e. the tweet’s existence via the depression of keys on a keyboard). Moreover, one brings about this event because of the mental intention to communicate the semantic content (propositions; speech acts) contained in the tweet. Since actuality entails possibility, it follows that it is possible for mental events to bring about physical effects because mental events (e.g. the intention to tweet) brings about physical effects (the creation of the tweet).
T and TT were unimpressed. They insisted that mentally events are causally effete (i.e. they cannot cause any physical effects). The only problem is that they made their case via tweets which convey semantic content based on their mental intention to communicate that content to folks like me. And so I charged them with a self-defeating position, i.e. arguing that mental events cannot cause physical effects by way of mental events that cause physical effects.
In response, T and TT appealed to physics and insisted that the ability of mental events to bring about physical effects violated physics in some way (e.g. by violating the law of conservation of energy).
This assumes (without argument) that mental events cause physical events by way of energy transfer. But one need not assume that at all. It could be that mental causation is a sui generis causal power.
At this point we need to take a step back and consider the following: of what am I more certain?
(1) That mental events can bring about physical effects (like semantically meaningful tweets)
(2) That the nature of the universe is such as to preclude the possibility of the mental affecting the physical
In my view, it isn’t even a contest. Obviously I’m more certain of (1). I’m more certain of it most clearly because I’m depressing keys on my keyboard as I speak and I’m doing so based on the intention of communicating to others. Remember, actuality entails possibility.
Moreover, as I already pointed out, mental causation could be sui generis. Thus, even if physics does preclude particular kinds of causation, it hardly follows that this includes mental causation.
Finally, I don’t agree with T and TT’s evaluation of physics. The observer effect is a well-established phenomenon in which minds can effect physical events merely by observing them. Consequently, I am left puzzled by the insistence of some that our current understanding of physics precludes the ability of the mind to affect the world.
To sum up my case: I intended to write this article; so much the worse for reductionism.