Full Idea
The two themes permeating the philosophical literature are that rationality is a matter of reasons, or that rationality is a matter of reliability.
Gist of Idea
Rationality is normally said to concern either giving reasons, or reliability
Source
Robert Nozick (The Nature of Rationality [1993], p.64)
Book Reference
Nozick,Robert: 'The Nature of Rationality' [Princeton 1995], p.64
A Reaction
Since a clock can be reliable, I would have thought it concerns reasons. Or an unthinking person could reliably recite truths from memory. There is also the instrumental view of rationality.
Related Idea
Idea 22662 In the instrumental view of rationality it only concerns means, and not ends [Nozick]