Catuṣkoṭi
from 400 BCE Present in the earliest Buddhist texts; systematised by Nāgārjuna
Four positions where logic ordinarily allows two: it is, it is not, it is both, it is neither — and sometimes all four are denied.
- Active
- from 400 BCE
- Where
- North India
- Also
- catuṣkoṭi
- Status
- In use
- Tradition
- Non-Western procedures
What it is
The catuṣkoṭi lays out four exhaustive positions on a question: affirmation, negation, both, and neither. In the earliest texts the Buddha uses it to decline questions by rejecting all four corners rather than choosing one.
Nāgārjuna turns it into an instrument. Where a question presupposes something false, every answer inherits the falsehood, and rejecting all four is the only honest response — not evasion but the finding that the question was malformed.
How it works
Set out the four corners for the question. Examine each against what the question presupposes. Where a corner can be sustained, take it. Where all four fail, the failure is informative: it shows the question rests on a presupposition none of its possible answers can survive.
The fourfold denial is the distinctive move and the one that looks like mysticism from outside. It is closer to the response of someone asked whether they have stopped beating their wife.
The moves, in order
- Set out the four corners: it is, it is not, it is both, it is neither
- Examine each against the presuppositions of the question
- If one corner survives, that is the answer
- If all four fail, the question is malformed
- Report the malformation rather than choosing a corner
The procedure
Proposition The question of whether the trust is a resident cannot be answered as asked.
- The form asks whether the entity is a resident for tax purposes, offering yes or no.
- It is a resident: false, because the trustee company is incorporated overseas and central management is exercised there.
- It is not a resident: also false, because the trust has a resident beneficiary presently entitled and its Australian-sourced income is assessed here.
- It is both: this is not a coherent position on the form, which allocates the whole entity to one status and drives every subsequent field from that allocation.
- It is neither: also not available, because the form requires an answer and the software will not accept a blank.
- All four fail, and they fail for the same reason: the form presupposes that residence attaches to an entity as a whole, and for a trust it attaches separately to the trustee, the trust estate and each beneficiary.
Therefore The question is malformed for this entity, and the correct response is not a corner but a statement that residence must be determined separately for the trustee and for each beneficiary.
Anyone who picks a corner here will produce a return that is wrong in a way no later field can correct. Rejecting all four is the only answer that does not propagate the error.
What it is good for
Questions built on a false presupposition, particularly in forms, surveys and legal tests designed for a standard case. The fourfold structure makes it visible that no available answer is right, which a straight refusal does not.
Where it fails
It is read as mysticism, constantly, and the reading is hard to dispel. A text that denies all four corners looks from outside like a refusal to think, and the tradition's own poetic register does not help.
There is also genuine disagreement about whether it violates non-contradiction. Some readings preserve classical logic by distinguishing the senses in which each corner is denied; others, notably Priest's, take it as evidence for a paraconsistent logic in which contradictions can be true. The texts underdetermine which is right.
And it is easily abused. Denying all four is available to anyone who wants to avoid committing, and nothing in the form distinguishes a malformed question from an inconvenient one.
Common misconceptions
That it rejects logic. Nāgārjuna argues with great precision and the fourfold denial is used to a specific end — showing that a question's presuppositions cannot be sustained — rather than as a general licence to say contradictory things.
Where it came from
Present in the Pali canon, where the Buddha declines certain metaphysical questions by rejecting all four corners. Nāgārjuna makes it central to Madhyamaka in the second century.
What became of it
Continuously debated within Buddhist philosophy and, since the 1970s, a serious topic in Western logic through the work on paraconsistency.
Lasting influence
It is the reason Madhyamaka can deny both existence and non-existence without simply contradicting itself, which is the doctrinal core of the school.
Why it still matters
Alive in Buddhist philosophy and in the logic of presupposition failure.
Put another way
A form with four boxes and a case that belongs in none of them.
Texts
Nāgārjuna, Mūlamadhyamakakārikā
Terse verse requiring a commentary. Garfield's translation with commentary is the standard English route.
Where to start
Read Garfield's translation of the first chapter. Twenty pages, and the method is fully visible.
The surprising bit
A second-century Buddhist argument is now cited in technical work on paraconsistent logic, and the question of whether Nāgārjuna was a dialetheist is an open one in contemporary logic journals.
In their own words
Not from itself, not from another, not from both, nor without a cause
Who held it
the Pali canon
Connections
The verdict
A precise instrument for presupposition failure that has spent two thousand years being mistaken for mysticism.