Haven't had a post in too long, and I hope to get back into things.
I was reading an article about dualism where they point out 6 reasons that naturalism is false and that dualism must be true, as evidenced by properties of the mind and brain. It makes sense to respond to each of the claims in turn, and to focus on how we know what we know, how we can demonstrate dualism or not, and where to go from here.
1) First-person access to mental properties
"This concept of your dream car is not something that people can see by looking at your brain structure. Physical properties can be physically accessed, but the properties of your dream car and privately accessed"
Although we are a bit far from publicly accessing as complex an object as a car, we can actually access brain states with various types of imaging and reconstruction. One interesting one is a reconstruction of concepts via fMRI by Tom Mitchell. Another is a movie reconstruction from brain activity by Jack Gallant. Both of these demonstrate that what was once privately held experiences can be publicly accessed as activity patterns in the brain. Note this is not "looking at your brain structure", it is looking at the process of the brain. Thus, the sorts of dichotomies present in this article between the mind and the structure of the brain are all strawmen.
2) Our experience of consciousness implies that we are not our bodies
"Common sense notion of personhood is that we own our bodies, but we are not our bodies"
My first reaction with this is to think:
"Common sense notion of the world is that it is flat, and unmoving"
Since when do we use common sense to determine truth? It might be an initial guide, but our experience with relativity and quantum mechanics should immediately make one wary about using common sense as the sole method for determining the truth of a claim. It is true that we have a label, we call "I" or "self" which seems separate from the body, but that is no argument that they are actually separate. It is easy to see that this label is not the entire picture, where we can push the boundaries. For example, the E. coli bacteria in our gut we often think of as separate from ourselves, and yet we cannot live without it, and the distinction between these beings and ourselves is quite a bit blurred. What about the mitochondria in our cells? Are the separate from you? Are they not?
It is a common pattern that, for any complex system, sharp distinctions are are rare. Animate vs inanimate, quantum systems vs classical, etc... To base ones objection to an idea because it isn't black and white is, frankly, childish.
3) Persistent self-identity through time
"When you change even the smallest part of a physical object, it changes the identity of that object. Every cell in your body is different from the body you had 10 years ago. If you are the same person you were 10 years ago, then you are not your physical body"
So, as your tire tread wears down from your car, it ceases to be your car? When your mechanic changes the spark plugs, it is no longer your car? "Your car" is the convenient label we give an object that has some form of permanence, whether it be a permanence of form or function. The label obviously has some limits as a result. Swapping every piece of one car with another, even if done gradually, may in fact change its identity (i.e. label) or is might not - depends on whether the label itself is useful. We aren't talking about some Platonic pure forms here, or a pre-scientific essence, neither of which are demonstrable.
When an amoeba splits, what about the identities of the resulting two? Is one of them the same original amoeba? Both of them? Neither (in which case the original one is simply gone)? Perhaps the simplistic picture of identity being used here is just not useful. The words may in fact not have any meaning.
So the label that we ascribe to "self" is perfectly fine 10 years later, despite the changes in cells, because there is some permanence of form and function. Each new brain cell, for example, fills the shoes of the ones that went before in much the same way that factory workers take shifts - the process continues, even if the components change over time. If the mind is the process of the brain, as stated before, then this is no problem. If the label "self" leads to contradictions when pushed too far, then perhaps the label or the way we imagine the label being used is no longer appropriate in those situations.
4) Mental properties cannot be measured like physical objects
"Physical objects can be measured (e.g. – use physical measurements to measure weight, size, etc.). Mental properties cannot be measured.
Stated without support, and contradicted by the evidence above for (1).
5) Intentionality or About-ness
"Mental entities can refer to realities that are physical, something outside of themselves. A tree is not about anything, it just is a physical object. But you can have thoughts about the tree out there in the garden that needs water."
I'm not sure if this statement is even defined - what does it mean to be "about" something, such that a physical object can't be "about" something. Mental states, as represented by brain activity, are correlated with physical reality, can have representations of that reality (mental models) which are essentially a form of correlated activity, so in that sense mental states can be about physical reality. Of course there can be limited examples of this sort of correlation on a much simpler level. The ripples on a pond are correlated with the stone dropped in, for example. There is a very big difference between mental states and ripples on a pond, clearly, but the the notion of correlation with physical reality is shared between the two. I'd have to wait for a better definition of "about", used in this context, to make a better response.
6) Free will and personal responsibility
"If humans are purely physical, then all our actions are determined by sensory inputs and genetic programming."
No argument there.
"Biological determinism is not compatible with free will, and free will is required for personal responsibility."
Libertarian free will is what is being implied here, and I'd have to agree. There are other forms of "free will" which is completely consistent with biological determinism, such as those proposed by Dan Dennett.
"Our experience of moral choices and moral responsibility requires free will, and free will requires minds/souls."
Sorry, this doesn't follow. If free will is an illusion, perhaps a useful one for a functioning society, then our experience of it is in no way evidence of its existence. You would need to demonstrate this claim, beyond saying "It feels like I have free will" or "It feels like I make moral decisions". Again, just because it feels like the Earth is flat and unmoving doesn't mean it is so.
So, in sum, we have evidence that the activity of the brain is identical to the mind. The claims made in the article quoted above amount to nothing but unsubstantiated assertions, and the appeal to so-called common sense and feeling deep down that it is true. In science we hold things to higher standards, and that is a good thing. To cling to dualism because it simply feels right is a desperate move.