Single Idea 6472

[catalogued under 7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff]

Full Idea

Continuity is not a sufficient criterion of material identity; it is sufficient in many cases, such as rocks and tables, where the appearances change slowly, but in others, such as the parts of an approximately homogeneous fluid, it fails us utterly.

Clarification

A 'homogeneous' has the same texture throughout, such as water

Gist of Idea

Continuity is a sufficient criterion for the identity of a rock, but not for part of a smooth fluid

Source

Bertrand Russell (The Relation of Sense-Data to Physics [1914], §XI)

Book Reference

Russell,Bertrand: 'Mysticism and Logic' [Unwin 1989], p.164


A Reaction

It might be debatable to what extent the 'parts' of a homogeneous fluid have identity. How many 'parts' are there in a glass of water? This seems, now, a problem for internalists; externalists can define the identity by the unseen molecules.