The brain in the vat and the burden of proof

Any reason to think it isn't true? One way around this is to shove the burden of proof to the other side. In fact, you can win any debate just by shoving the burden of proof to the other side, because you can ask for proof for the proof, and then proof for the proof for the proof, and then proof for the proof for the proof for the proof, and then proof for the proof for the proof for the proof for the proof......., until your opponent gets tired. 

Six Naturalistically Problematic features of Reason

(1) Reason isn’t just pragmatically useful; indeed, it is self-refuting and circular to assert that it is.

(2) Reason isn’t a contingent, local, perspectivalist feature of our evolved nature. It has universal applicability. Evolution produces local, contingent dispositions, not universal, necessary ones.

 (3) Reason is intrinsically normative.

(4) Reason takes us beyond appearances to the hidden, intelligible structure of the world.

(5) In contrast to the senses, which put us in contact with objects via causal chains, reason is not mediated by mechanisms that could be selected by evolutionary processes; rather, reason puts us in immediate, direct contact with the rational order.

(6) Reason is active and involves agency (for example, it isn’t Sphexish); sensation is passive. 

See J. P. Moreland's review here. 

What is the evidence...

That our sense experience is veridical? That we are not brains in vats and our experience is not systematically false?

Why mental states are not physical states

If mental states are physical states, then the truth about what someone believes should follow necessarily from the state of the brain/physical world. But it doesn't. If we line up all the physical facts, we have every atom traced, the argument from The brain is in state X therefore he must believe, say, that God exists, cannot follow necessarily. The state of the physical always leaves the state of the mental indeterminate. But what my thought is about is determinate, not indeterminate. Therefore my belief is not a physical state.

C. S. Lewis on authority

“Don't be scared by the word authority. Believing things on authority only means believing them because you've been told them by someone you think trustworthy. Ninety-nine per cent of the things you believe are believed on authority. I believe there is such a place as New York. I haven't seen it myself. I couldn't prove by abstract reasoning that there must be such a place. I believe it because reliable people have told me so. The ordinary man believes in the Solar System, atoms, evolution, and the circulation of the blood on authority -because the scientists say so. Every historical statement in the world is believed on authority. None of us has seen the Norman Conquest or the defeat of the Armada. None of us could prove them by pure logic as you prove a thing in mathematics. We believe them simply because people who did see them have left writings that tell us about them: in fact, on authority. A man who jibbed at authority in other things as some people do in religion would have to be content to know nothing all his life.” 
― C.S. Lewis, The Case for Christianity

Is it a mistake for Nagel to concentrate on reductive materialism?

I think some confusion is generated by his use of the term “reductionism” to describe the naturalistic position of which he is critical. Materialism is typically divided into three types, eliminative, reductive, and non-reductive materialism. On the face of things, by concentrating on reductive materialism, it might seem that he is letting the non-reductive materialists off the hook with his arguments, and this perhaps comprises the largest group of philosophers that call themselves materialist.

William Hasker, in The Emergent Self, (Ithaca, 1999), developed a tripartite definition of minimal materialism which, I believe works also for naturalism. That is, I don’t think any view can be thought to be genuinely naturalistic unless it satisfies these three requirements. And I think a position with these three characteristics is what Nagel is thinking of when he talks about reductive materialism. It is the view that

1)      At the basic level, reality is mechanistic. That is, it lacks intentionality, subjectivity, purposiveness, and normativity. None of these items can enter into a description of reality at the basic level of analysis.

2)      The basic level of analysis (which we typically call physics), is causally closed.

3)      Whatever else exists must supervene on the basic level. It must be the sort of think that must be the way it is because the physical is the way it is.

Andrew Melnyk maintains that “Naturalism claims that nothing has a fundamentally purposeful explanation…Naturalism says that whenever an occurrence has a purposeful explanation, it has that explanation in virtue of certain nonpurposeful (e.g. merely causal) facts.” And the failure to the mental on the ground floor of reality, so say that our minds can understand the world,  ultimately, because mind is fundamental to reality and not simply a byproduct of it, is what Nagel sees as ultimately wrong with the all the positions he is calling “reductivist.”

Nagel on Plantinga

I say this as someone who cannot imagine believing what he believes. But even those who cannot accept the theist alternative should admit that Plantinga’s criticisms of naturalism are directed at the deepest problem with that view—how it can account for the appearance, through the operation of the laws of physics and chemistry, of conscious beings like ourselves, capable of discovering those laws and understanding the universe that they govern. Defenders of naturalism have not ignored this problem, but I believe that so far, even with the aid of evolutionary theory, they have not proposed a credible solution. Perhaps theism and materialist naturalism are not the only alternatives.