Holds that mathematics is not about an abstract reality at all, but is a game of manipulating meaningless symbols according to agreed-upon rules — true only in the sense of being validly derived, not in the sense of describing anything.
The direct challenge to perennialism: holds that there is no “pure,” unmediated mystical experience at all — every mystical experience is actively shaped, from the moment it occurs, by the mystic’s pre-existing language, concepts, expectations, and cultural and religious background.
Holds that mathematics is a construction of the human mind, not a description of an external reality or a formal symbol-game — so a mathematical statement is only true if a mental construction proving it actually exists, which leads intuitionists to reject some classical logical laws.
A landmark, carefully controlled clinical study finding that psilocybin, administered in a supportive clinical research setting, could reliably occasion experiences meeting standard psychological criteria for a “complete” mystical experience — comparable in structure to those reported in spontaneous religious and contemplative contexts — with many participants rating it among the most personally and spiritually significant experiences of their lives at long-term follow-up.
Proposes that mathematical objects like “the number 2” have no intrinsic identity at all — they are defined entirely by their position within a structure (a pattern of relations), the way a chess knight is defined by how it moves rather than by what it is made of.
An interdisciplinary research program using brain-imaging technology to study what happens in the brain during prayer, meditation, and other religious or spiritual practices — including studies of Tibetan Buddhist meditators and Franciscan nuns in prayer showing consistent, measurable changes in brain regions associated with attention and spatial orientation.
Agrees with skeptics that abstract mathematical objects like numbers don’t literally exist, but holds mathematics is still worth using — the way a novel’s characters don’t exist but the story is still worth telling — because it is a useful, convenient fiction rather than a body of literal truths.
Holds that determinism is true — every event, including every human decision, is the fixed consequence of prior causes and the laws of nature — and that this is genuinely incompatible with free will, which therefore does not exist.
Holds that free will is real and requires indeterminism to be true — that some human choices are not fully fixed by prior causes, leaving room for a person to be the genuine, undetermined origin of their own action.
A tightly formal argument for incompatibilism: if determinism is true, our present acts are the necessary consequence of the distant past plus the laws of nature — neither of which is ‘up to us’ — so our present acts are not ‘up to us’ either, however things feel from the inside.