Full Idea
That 'cats are animals' is often cited as an analytic truth. But (as Putnam points out) the inability to imagine this false is just a lack of imagination. They might turn out to be radio-controlled plastic spies from Mars.
Gist of Idea
Only lack of imagination makes us think that 'cats are animals' is analytic
Source
Gilbert Harman (Thought [1973], 6.7)
Book Reference
Harman,Gilbert: 'Thought' [Princeton 1977], p.105