Yesterday I wrote a reply to a science blogger, Bernardo Kastrup, who wrote a critique of an earlier blog post of mine. He has now written a reply to my reply. I find these blog discussions very useful – each side can take their time to compose their argument and we can usually get down to the key issues.  They can also be fun.

Kastrup begins, unfortunately, with a bit of whining.

While I appreciate his having taken the time to reply, I am also somewhat surprised by the sheer amount of space he dedicates to ad homenen attacks on me, which dilutes his argument and the quality of the debate.

Sure, I got a bit snarky in my reply, but I will point out that my criticisms were all valid. Also my two sharpest barbs were direct quotes from Kastrup against me. It’s bad form, in my opinion, to open up a debate with personal attacks and then whine when you get the exact same thing back.  But fine – let’s get past that and focus on the substance of the discussion. His next point, however, is also about form. He writes:

This is correct. So let me take the opportunity to be explicit: I only read the post that was forwarded to me, and my comments were based on that alone. If Novella’s position in other posts was more nuanced, I’ve missed that, since I do not know Novella’s work.

I don’t expect those who comment on my blog posts to read large numbers of posts by me before commenting. That would be unreasonable. What I do expect is that they will interpret my posts fairly and not criticize me for not exploring issues that I have explored elsewhere. It’s impossible to cover every side issue in every blog post, so I do rely upon prior articles to cover these side issues.

The problem with Kastrup’s original criticism of my post was not that he did not read other posts by me – it was that he misinterpreted the post he did read. He does nothing to address this criticism by me in his new post, but rather entirely misses the point. In his criticism he accused me of assuming causation from correlation, but I never did. In the very post he was commenting on I never said anything about proof – I said that the conclusion that the brain causes the mind is the best inference from the data available, and I added that not only is there a correlation but it has the proper temporal relationship (brain activity and changes precede mental activity and changes), that there are no other plausible hypotheses, and that other hypotheses that can account for the correlation add unnecessary elements and so violate Occam’s razor. Kastrup distilled all of that to the claim that I was saying correlation equals causation. That was the straw man that he flogged in his criticism.

In his new reply he does not acknowledge his error, or point out where I was wrong, or even give any indication that he understands his error.

He continues:

But if this is an error on my side, Novella has committed the exact same error already in the title of his reply: Had he read anything of my work besides the post he is replying to, he would have seen that I am precisely not a Dualist, but a monist (for instance, see this).

OK, I admit it’s easy to think that I am calling Kastrup a dualist, but I actually never did. I merely said that he was inserting himself into a discussion about dualism. I only referred to his position as “metaphysical.” I deliberately did not call him a dualist or address his specific flavor of metaphysics because that is a different discussion. For those interested, Kastrup believes that reality is a projection of consciousness, and the brain acts mainly as a filter. You can read his description here.

Kastrup is wrong about me calling him a dualist (an unwarranted assumption on his part), and seems to reflect a pattern of not carefully reading those with whom he disagrees. Finally, though, we get to the meat of the discussion when he writes:

In my article, I mentioned several models for the relationship between mind and brain under which the exact same phenomenology is expected: Changes to brain states leading to changes in subjective experience. My post was very clear about this, so I am surprised Novella seems to have difficulties on this point. To be explicit: If the brain merely modulates subjective experience (through filtering and/or localization, for instance), then one would expect precisely that disturbances in the brain would impact the modulation process and, thereby, alter subjective experience. I invite Dr. Novella to acquaint himself a little more with these other explanatory models of mind-brain interaction so we can continue with the debate in a more productive manner.

I invite Kastrup to acquaint himself a little further with my prior deconstructions of this position. I actually did address this, to some extent, in my prior post to which he is responding. It’s not just that brain states correlate with mental states, and it is not even just that brain states precede mental states – further, there is no other hypothesis that does not add unnecessary elements, the equivalent of light switch fairies – a point Kastrup ignores.

The problem with positions like this is that they add nothing to our understanding of the mind as a phenomenon, and they make no testable predictions that would distinguish them from the simpler explanation that the brain causes mind. Kastrup hides behind the fact that there are no good metaphors for the brain as “filter”, but that is not a strength of his position. I get the sense that we are talking past each other a bit, perhaps because he is approaching this issue as a philosopher and I am approaching it like a scientist. Show me evidence and make predictions, give me operational definitions and clearly defined models. He want to work with vague and poorly understood metaphors and talks about absolute proof.

The problem, from a scientific point of view, is that the notion that the brain modulates consciousness becomes operationally inseparable from the notion that the brain causes consciousness, at least in terms of the experimental relationship between brain function and mental function. When I electrically stimulate part of the brain, that affects mental function. There does not seem to be any practical limit to the degree to which we can temporarily or permanently change mental function by altering brain function, and we are steadily progressing in our ability to model what parts of the brain are doing what. There doesn’t seem to be anything coming from outside the brain – but worse, the concept is completely unnecessary. It is sliced away cleanly by Occam’s razor.

Kastrup tried to address the Occam’s razor argument, but failed to do so. First he missed my main point, that by invoking Occam’s razor I was clearly not relying on mere correlation. His response on this score was a non sequitur – that if NDEs are real Occam’s razor favors some flavor of dualism (whatever you call it). First, this is a shaky premise at best (and I think false), but further I also disagree with his logic. If NDEs were real as he characterized them what we would have in an anomaly to be investigated. Introducing noncorporeal mental function would still be a massive new element that would need independent verification. But I agree it would then at least be a reasonable hypothesis. Of course with a premise that is shaky to false, the introduction of something as extraordinary as mental function apart from the brain is completely unwarranted.

Along this line, Kastrup then repeats his contention that there is evidence for mind apart from brain:

To repeat a point I made in my original post: There is strong scientific evidence for mind states that indeed do not correlate to brain states. So if anything is to be scientifically inferred from current observations, I’d say it is that mind states are not caused (but merely modulated) by brain states.

This is an absurd premise on his part. There is absolutely no scientific consensus that there is reliable evidence for mind apart from brain. He is citing controversial (at best) claims as support for his position. What he calls strong scientific evidence is laughable, is not generally accepted by the scientific community and only persists on the fringe. He is using clairvoyance to substantiate claims for ghosts. I have already addressed the near death experience point, which he does not address in his new post so I guess we’ll put that aside for later. He does bring back up the psilocybin example. He cites another post of his, in which he argues:

The first materialist rebuttal is this: Brain activity is composed of both excitatory processes and inhibitory processes. Excitatory processes generate – well, correspond to – subjective experiences (perceptions, feelings, ideas, etc.). Inhibitory processes, on the other hand, dampen excitatory processes down, preventing them from arising. So the idea is that, when brain activity is impaired or reduced, the inhibitory processes are blocked. The consequence is that excitatory processes – which would otherwise be stopped before taking root – can now grow to become major subjective experiences.

 This answer appears wrong on an empirical basis. If it were correct, one should observe not only a reduction of activity in certain brain regions (i.e. the inhibitory processes being blocked), but alongside it also a significant activation of other brain regions (i.e. the excitatory processes that can now take root). However, the study that identified the dampening of brain activity as the mechanism of action of psychedelics did not observe any significant activation elsewhere in the brain.

This is all hopelessly wrong.  First Kastrup is overly simplistic (to the point of being wrong) in seeing brain function as either excitatory or inhibitory. He is confusing different levels of brain activity – this is an accurate description of the effects of specific neurotransmitters on specific receptors on neurons, they will either increase or decrease the activity of those neurons. But this is not a good description of how different parts of the brain interact. I gave a brief description of this in my last post, but to expand on this – different parts of the brain are active in processing information from other parts of the brain. They modify how the other parts of the brain are working, or the net effect of that processing on our thoughts, feelings, behaviors, and net subjective experience. When you remove one element from the committee of voices contributing to net experience, that experience changes.

It may be that some some other “voices” are more prominent, because they are not being modified, inhibited, or drowned out by other parts of the brain. Kastrup simplistically interprets this as requiring an increase in raw activity in some part of  the brain, but this is not true. Overall activity can still be decreased.

He gives as an example the intense mystical experiences caused by some drugs or during out of body experiences. The latter is now known to be caused by inhibiting brain regions, not enhancing them. Feeling inside ones body is an active neurological process. Inhibiting that process and decreasing overall brain activity can result in an OOB experience. Likewise the turning off of reality testing and rational parts of the brain will cause an intense mystical experience by  decreasing overall brain function.

Further, this is preliminary research and neuroscientists are still debating how to interpret it, so it is hardly a solid premise with which to discard the materialist paradigm. Previous PET studies showed that psilocybin increased activity in certain brain regions. Now an fMRI study shows that activity is decreased. This probably has something to do with the fact that PET scan and fMRI are measuring different things and inferring brain activity from that – so perhaps some aspects of metabolism are decreased and others increased. We need further research to sort this out. But either way – none of it breaks the predictions of materialism, as Kastrup claims.

Kastrup also makes the simplistic and wrong assumption that intensity of experience must equate to greater brain activity (in the purely materialist model). The massive frontal lobes, however, can have a largely calming effect. They can be furiously active while having the net effect of modulating emotions and experience specifically to make them less “intense,” from a subjective and emotional point of view. Anyone who has dealt with a patient who has had frontal lobe damage (and decreased brain activity) will know this to be true. Intensity of experience does not equal intensity of neuronal firing.

Kastrup concludes:

In conclusion, I believe that he did not at all counter any of the points I originally raised. I’m certainly willing to continue the debate if Dr. Novella addresses, with more substance, the contents of the articles I originally linked to as part of my original post, instead of ignoring them as he has done so far.

It’s easy to claim that the other person in a debate did not counter your points when you ignore the counter arguments or misinterpret them. Kastrup has only succeeded in piling logical fallacies on top of logical fallacies.

Let’s review:

Kastrup claimed that I assumed causation from correlation. False – I made a much more careful and logically valid argument, which I have now pointed out twice. Kastrup has failed to address this correction.

Kastrup claimed that NDEs are strong evidence for mind separate from brain. False, NDEs are not evidence of this, and at best are highly controversial claims. If he wants to pursue this point further he really should read my previous article on the topic which I linked to.

Kastrup claimed that I called him a dualist. False – I merely said his position was metaphysical, which it is (it is also arguably dualist, but that’s a semantic point).

Kastrup claims that the psilocybin evidence contradicts the predictions of materialism, and that I failed to understand this point. False and false – as I describe in detail above, Kastrup’s argument is entirely based on his own simplistic misunderstanding of neuroscience. He should at least exhibit a little tiny bit of humility when confronting neuroscientists about neuroscience (which he does also here  – apparently I am not the first neuroscientist to call his understanding of neuroscience “naive”). This doesn’t mean we’re right and he’s wrong, but it should at least give him pause. I know I get very concerned about my own understanding of a topic if experts in the field contradict me. What Kastrup is doing (with NDEs and the psilocybin example) is latching onto preliminary or controversial evidence and then treating it as a solid scientific premise. This is a common ploy of pseudoscientists, but does not make for convincing arguments.

Kastrup claims that I did not counter any of his points. This is also demonstrably false – see above.

I too am willing to continue this discussion. I ask that Kastrup take a deep breath and read my posts fairly and with a sincere attempt to understand and address my actual positions. Then maybe we can move forward.