Lifeboat Foundation

In response to Bernardo Kastrup’s scathing criticisms of materialist explanations of the states of consciousness induced by psychedelics, David Nutt argues that we don’t need to adopt an untestable metaphysical worldview to explain the subjective richness of psychedelic experiences.In response to Bernardo Kastrup’s scathing criticisms of materialist explanations of the states of consciousness induced by psychedelics, David Nutt argues that we don’t need to adopt an untestable metaphysical worldview to explain the subjective richness of psychedelic experiences.

Let’s start with where we agree. It doesn’t make intuitive sense that alterations in (increased) complexity of brain waves could explain the whole range of subjective experiences that are reported under the influence of psychedelics. I agree they probably don’t in a direct sense — it seems to me much more likely that they are correlated because they both derive from a common change in another system or systems. Despite Bernardo’s criticisms and scepticism, I think we can plausibly develop theories as a result of neuroscience and neuroimaging research coupled with simultaneous acquisition of subjective effects that help explain the altered state of consciousness produced by psychedelics.

Where those might be is the question — and I will come back to it later — but at this point I think it is reasonable to suggest that the primary visual hallucinations (the Christmas tree lights) probably reflect a psychiatry-induced disruption of the layer 5 neurons in the visual cortex. This would degrade the ability of the complex cortical network that creates vision by integrating retinal inputs. Physiological studies of the neuronal workings of non-human visual systems predict that simple geometric shapes, colours and movement are the primary processes that are extracted from retinal inputs and from which more complex visual schema are then created. Psychedelics disrupt these higher-level constructions so allow the user to “see” the primary workings of the visual system that are not normally accessible to consciousness.

The 25-year bet between neuroscientist Chris Koch and philosopher David Chalmers is settled. Consciousness, on the other hand, is not.

A case of wine was put on the line.

This is according to a report by Science Alert published on Tuesday.

A 25-year-old wager on the source of consciousness between German-American computational neuroscientist Christof Koch and Australian philosopher and cognitive scientist David Chalmers has come to a close with the first one admitting defeat.

Continue reading “A brain scientist and a philosopher have resolved a 25-year-old wager on consciousness” »

Two rival theories about the basis of perception went head-to-head in neuroscience experiments, but advocates of “losing” idea aren’t conceding yet.

Twenty-five years ago, a neuroscientist and a philosopher bet a case of fine wine on whether scientists would have cracked the neural basis of consciousness by 2023. Now, one of them conceded the prize.

By Alexis Wnuk

Christof Koch wagered David Chalmers 25 years ago that researchers would learn how the brain achieves consciousness by now. But the quest continues.

The foremost physiological effect of psychedelics in the brain is to significantly reduce activity in multiple brain areas, which contradicts the mainstream reductionist expectation. Physicalist neuroscientists have proposed that an increase in brain noise explains the subjective richness of a psychedelic experience, but a psychedelic experience isn’t akin to TV static, argues Bernardo Kastrup.

Before 2012, the generally accepted wisdom in neuroscience was that psychedelic substances—which lead to unfathomably rich experiential states—stimulate neuronal activity and light up the brain like a Christmas tree. Modern neuroimaging, however, now shows that they do precisely the opposite: the foremost physiological effect of psychedelics in the brain is to significantly reduce activity in multiple brain areas, while increasing it nowhere in the brain beyond measurement error. This has been consistently demonstrated for multiple psychedelic substances (psilocybin, LSD, DMT), with the use of multiple neuroimaging technologies (EEG, MEG, fMRI), and by a variety of different research groups (in Switzerland, Brazil, the United Kingdom, etc.). Neuroscientist Prof. Edward F. Kelly and I published an essay on Scientific American providing an overview of, and references to, many of these studies.

These results contradict the mainstream metaphysics of physicalism for obvious reasons: experience is supposed to be generated by metabolic neuronal activity. A dead person with no metabolism experiences nothing because their brain has no activity. A living person does because their brain does have metabolic activity—or so the story goes. And since neuronal activity supposedly causes experiences, there can be nothing to experience but what can be traced back to patterns of neuronal activity (otherwise, one would have to speak of disembodied experience). Ergo, richer, more intense experience—such as the psychedelic state—should be accompanied by increased activity somewhere in the brain; for it is this increase that supposedly causes the increased richness and intensity of the experience.

A recent study on monkeys found that stimulating a certain part of the forebrain wakes monkeys from anesthesia.

How can the mindless microscopic particles that compose our brains ‘experience’ the setting sun, the Mozart Requiem, and romantic love? How can sparks of brain electricity and flows of brain chemicals literally be these felt experiences or be ‘about’ things that have external meaning? How can consciousness be explained?

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Continue reading “Keith Ward — Why is Consciousness so Mysterious?” »