Full Idea
"The same" is a fragmentary expression, and has no significance unless we say or mean "the same X", where X represents a general term. ...There is no such thing as being just 'the same'.
Gist of Idea
Being 'the same' is meaningless, unless we specify 'the same X'
Source
Peter Geach (Mental Acts: their content and their objects [1957], §16)
Book Reference
Geach,Peter: 'Mental Acts: Their content and their objects' [RKP 1971], p.69
A Reaction
Geach seems oddly unaware of the perfect identity of Hespherus with Phosphorus. His critics don't spot that he was concerned with identity over time (of 'the same man', who ages). Perry's critique emphasises the type/token distinction.