Just some additional notes from the archive. As I said in Slide #15, by Physicalism or Materialism, or more accurately, Reductive Physicalism, I mean the combination of three distinct ideas.
We are Physical Things—We are basically a physical thing with both mental and physical characteristics rather than a composite of a purely mental thing and a purely physical thing.
Mind-Body Dependence—What mental characteristics we have depends on what physical characteristics we have.
Mind-Body Reductionism—Mental characteristics are just (configurations of) physical characteristics , with other names.
And Mind-Body Dependence (Slide #17) itself is a composite of the following three ideas:
(1) Physical characteristics are more fundamental than and explain mental characteristics.
(2) Mental characteristics supervenes on physical characteristics–Two things have different mental characteristics only if they have different physical characteristics.
The idea of Supervenience throws some students off (and come fancy name too). You can remember the basic idea behind this slogan:
No mental difference without a physical difference.
To get what is being said, consider four possible options regarding two entities–let’s say two brains A and B.
Option 1: A and B are physically exactly alike / A and B are mentally exactly alike.
Option 2: A and B are physically exactly alike / A and B are mentally different. (X)
Option 3: A and B are physically different / A and B are mentally exactly alike.
Option 4: A and B are physically different / A and B are mentally different.
(Note that when I say “physically exactly alike”, I mean exactly. Not just to the naked eyes, for instance, but down to the molecular level.) To say that mental characteristics supervenes on physical characteristics is to say that Option 2 is not possible while all of the other three options are possible. Since the other three options are still possible, it will also follow that some physical differences are “mentally irrelevant”, i.e., just because two things are physically different, it doesn’t follow that they will be mentally different.
How does Supervenience related to Dependence? Mind-Body Supervenience is the weaker doctrine in that all it says is that there is a certain correlation between the mental and physical properties of a thing. This correlation is expressed by our saying previously that Option 2 is not possible–but Options 1, 3 and 4 are possible. But why might it be that such a correlation holds? You might think that it’s because it is the underlying physical difference that makes it possible for there to be a mental difference. Now we are saying more than that there is a certain correlation. We are saying that what mental properties a thing has (and whether it has any mental properties at all) is explained by what physical properties it has. So when we have both ideas (1) and (2) together, we have Mind-Body Dependence.
Alright, on to Mind-Body Reduction:
Mind-Body Reductionism: Mental characteristics are just (configurations of) physical characteristics, with other names.
Mind-Body Dependence is about how the mental and physical characteristics of a thing are related to each other. In principle, it allows for the possibility that the mental characteristics of a thing are a special sort of characteristics that are not just the physical aspects of the thing. With Mind-Body Reduction, with have a more stringent view–mental properties are basically nothing other than physical properties under a different name. On this view, all that is meant by your feeling a certain itch literally just is that your nervous system and brain are in a certain state. Or all that is meant by your having a certain thought (“I am sitting in an café”) literally just is that your brain is in a certain configuration. Another way to say all this is that the mental properties ultimately turn out to be just a bunch of physical properties, and that is all.