Psychedelic substances, such as psilocybin mushrooms, LSD, and ayahuasca, do much more than generate sensory hallucinations. Users often come away with a sense of having gained deep insight into the nature of reality – even if what that insight is, and what is so special about it, can be hard to communicate. Anthropologist Nicolas Langlitz associates it with the “perennial philosophy” – an old idea, popularized by Aldous Huxley, that all world religions communicate the same basic truth. Years after writing the book The Perennial Philosophy, Huxley tried mescaline and LSD and became convinced that psychedelics provide a shortcut to the kinds of mystical experiences that would put us in touch with that basic reality – what he called the “world mind”. Langlitz is skeptical that psychedelics really do communicate some kind of metaphysical truth. In this interview, we discuss what psychedelics do reveal, if anything, and what the relationship is between experience and knowledge.
Next week: Kit Fine: Metaphysical Ground
0:20 – Intro to Nicolas Langlitz
1:05 – Anthropology and philosophy
10:06 – Nick’s research on psychedelics
22:23 – Perennial philosophy (Huxley)
29:20 – Indescribable?
33:09 – Materialism and mysticism
41:14 – Diversity v. unity of psychedelic experience
47:40 – Validity and expression of the psychedelic experience
59:50 – Place of psychedelics in society
For some time, the answer to this perennial question was thought by many to be “justified true belief”. If I believe X to be true, I have good reason for believing X to be true, and X really is true, then I know X. In 1963, Edmund Gettier published a now legendary three-page paper titled “Is Justified True Belief Knowledge?” in which he gave two examples of justified true belief that did not constitute knowledge. Since then, epistemologists have mostly agreed that there’s some extra ingredient requisite for knowledge but have disagreed about what it is. After drawing out Gettier’s examples, Peter Klein explains that there are two major camps. The first he calls etiology of belief: theories in which the extra ingredient has to do with how the belief was attained. Reliabilists, for example, argue that a justified true belief counts as knowledge if the belief is arrived at via a method that reliably delivers accurate beliefs. Klein belongs to the second camp: quality of evidence theories, which have to do with the strength of the justification, not the cause of the belief. Klein defends his own preferred quality of evidence theory: defeasibility theory, which involves the existence or absence of “defeaters” for the justification.
Suppose you know X. How do you know? Maybe you know because of Y. How do you know Y? Maybe the answer is Z. How do you know Z?
This is the regress problem of knowledge, also called the Agrippan trilemma and the Münchhausen trilemma. It is based on the supposition that if we claim to know something, we must have a reason for it and that reason must itself be something that we know. This leaves open four possible solutions. One is skepticism, the belief that we have no knowledge. The most common is foundationalism, which posits certain basic facts that require no external reasons to be justified. Another option is coherentism, which solves the problem via a kind of circular reasoning or justification loop. And finally, there is infinitism, the view that there is no end to the regress. For any chain of justification, the final member of the chain will always be unjustified, and it is always possible to go looking for further reasons of reasons of reasons. As infinitist Peter Klein puts it, knowledge is never “settled”. Even so, says Klein, it is still possible to have knowledge. In this interview, Klein first argues why he thinks coherentism, foundationalism, and a certain kind ofskepticism all fail. He then explains his own account of justification, as “something that we do”, and how it makes the infinitist picture look more plausible than it first seems.…