Hume’s gap (is–ought)

Compiled with AI assistance and selectively reviewed. Please consult the cited passages; the books remain the authoritative source. About this companion

Editorial synthesis · provisional

Definition

Hume’s is–ought gap names the logical limit on deriving an ethical demand from description alone. The author retains that limit while contesting the image of a living world made entirely of value-free facts. Viability supplies real better-and-worse conditions; sustaining plural beings nevertheless remains an explicit ethical commitment, not a theorem extracted from the Laws of Change.

Explanation

AB argues that life already has stakes and that the gap opens only in a falsely divided world of dead facts and free-floating values. This is the author’s substantive reply to Hume, not merely acceptance of the objection. The subsequent qualification locates stakes in self-maintaining life and openly states the commitment that plural strivings should continue together.

PB makes the logical boundary especially explicit. Its formal compossibility module can model coexistence without ruin but cannot supply why one ought to choose it. Both its summary and detailed caveat say that bindingness comes from ethics rather than mathematics.

RB2 similarly requires an evaluative premise before drawing ethical conclusions about living beings. Hume’s separate problem of causation, also discussed in the sources, is relevant background to the author’s response and must not be mistaken for the is–ought problem itself.

Scope and attribution

AB supplies the named Hume discussion; PB and RB2 preserve explicit logical qualifications. RB1/RB3 causation passages are distinct, not independent definitions of this gap.

AB — The Actual Book

The logical gap is retained while the author rejects a value-free picture of life and states a positive commitment.

Occurrence locators: 179, 180.

PB — The Possible Book

Formal compossibility does not prove bindingness; the is–ought residue remains explicit.

Occurrence locators: 37, 63, 105, 147, 155, 156, 175, 181.

RB2 — The Real Book, Volume II: Becoming Is Being

Ecological and ethical conclusions require additional evaluative premises.

Occurrence locators: 176, 296.

Background used in the editorial explanation

Hume’s causation problem is distinct from is–ought; the thinker-register causation notice and general evolutionary metaethical note are background. Related passages on AB p.180 are assessed separately.