Full Idea
Is it not reasonable to say that motion is not without the mind, since if the succession of ideas in the mind become swifter the motion, it is acknowledged, shall appear slower without any alteration in any external object.
Clarification
'Without' here means outside
Gist of Idea
Motion is in the mind, since swifter ideas produce an appearance of slower motion
Source
George Berkeley (The Principles of Human Knowledge [1710], §14)
Book Reference
Berkeley,George: 'The Principles of Human Knowledge etc.', ed/tr. Warnock,G.J. [Fontana 1962], p.71
A Reaction
An intriguing argument, based on what is now the principle of slow-motion photography. Fast minds slow down movement, like great tennis players. By what right does Berkeley say that the external subject is unaltered?