Why One Ought to (At Least) Be a Property/Event Dualist

This post will be short. I don't think it takes much to get to property dualism given our knowledge of mental states, events, etc. I shall also borrow from the influential contemporary philosopher Richard Swinburne. [1]

There are mental and physical events. By 'event' here I just mean, following Swinburne, properties instantiated in substances at times.  A mental event is one to which the subject necessarily has privileged access. The event that is my being in pain or my thinking about something might be knowable by observing my behavior, or even looking at my brain, but I would still have one more way of knowing about these events than you: I can actually experience the events. No matter how you might come to know about the event, I can just as well use your method. But I am still one ahead of you, because I have a direct experience of these events, which is a means of knowing to which you have no access whatever. A physical event is an event to which the subject does not necessarily have privileged access. The physical event that consists in a number of neurons in my brain firing about at a certain time is knowable by me just as well as it is knowable by you. You come to know about this event by observing my brain and, similarly, I might do the same on video. Or, for a simpler example, the physical event that is your computer's being a certain size is not such that you have privileged access to that information. Any way you can know about this event I can equally well know about it through the same means. So there is no privileged access with respect to physical events.

And now it becomes evident that these events are truly distinct from one another.

Swinburne doesn't do this but it might help to explain why. The following is "Leibniz's Law:"

(LL) For all x and y, if x = y, then, for any property P, x has P just in case y has P.

That is just a fancy way of saying that if x is identical with y then x and y have exactly the same properties. All mental events have the property of being such that the subject (in which they inhere) necessarily has privileged access to them. All physical events, as we have seen, lack this property. So it cannot be the case that mental events just are physical events. Mental events are distinct from physical events. Since events are simply properties instantiated in substances at times, what makes an event a mental event is that mental properties are instantiated. So mental properties are truly distinct from physical properties. Swinburne puts it like this,"Consequently, [mental events] must be distinct from brain events...A neurophysiologist cannot observe the quality of the color in my visual field, or the pungency of the smell of roast beef which I smell."[2]

[1] Richard Swinburne. Is There a God?. (Oxford University Press, 2010). Pg. 64-65.
[2] Ibid. Pg. 65.