Full Idea
Every instrument will be made best if it serves not many purposes but one.
Clarification
'Purpose' is the Greek word 'telos'
Gist of Idea
The best instruments have one purpose, not many
Source
Aristotle (Politics [c.332 BCE], 1252b03)
Book Reference
Aristotle: 'Politics', ed/tr. Sinclair,T.A. /Saunders,T. [Penguin 1992], p.57
A Reaction
Sound like a good general truth, but not a universal truth. Swiss army knife. Ship in a bottle. Pins. Wrapping paper.