Single Idea 5750

[catalogued under 2. Reason / A. Nature of Reason / 1. On Reason]

Full Idea

Consistency is a modal notion: a set of propositions is consistent iff all the members of the set could be true together.

Clarification

'Could' is a modal notion, depending on possibility rather than actuality

Gist of Idea

Consistency is modal, saying propositions are consistent if they could be true together

Source

Joseph Melia (Modality [2003], Ch.6)

Book Reference

Melia,Joseph: 'Modality' [Acumen 2003], p.129


A Reaction

This shows why Kantian ethics, for example, needs a metaphysical underpinning. Maybe Kant should have believed in the reality of Leibnizian possible worlds? An account of reason requires an account of necessity and possibility.