Full Idea
Frege disagree that logic should merely describe the laws of thought - how people actually did reason. Logic is essentially normative, not descriptive. We want the one logic which successfully tracks the truth.
Gist of Idea
We should not describe human laws of thought, but how to correctly track truth
Source
report of Gottlob Frege (Begriffsschrift [1879]) by Jennifer Fisher - On the Philosophy of Logic 1.III
Book Reference
Fisher,Jennifer: 'On the Philosophy of Logic' [Thomson Wadsworth 2008], p.17
A Reaction
This explains Frege's sustained attack on psychologism, and it also explains we he ended up as a platonist about logic - because he wanted its laws to be valid independently of human thinking. A step too far, perhaps. Brains are truth machines.