Quotes from Gottlob Frege

...one can hardly deny that mankind has a common store of thoughts which is transmitted from one generation to another.

Every good mathematician is at least half a philosopher, and every good philosopher is at least half a mathematician.

A scientist can hardly encounter anything more desirable than, just as a work is completed, to have its foundation give way.

I do not begin with concepts and put them together to form a thought or judgement; I come by the parts of a thought by analysing the thought.

Thus the thought, for example, which we expressed in the Pythagorean theorem is timelessly true, true independently of whether anyone takes it to be true. It needs no bearer. It is not true for the first time when it is discovered, but is like a planet which, already before anyone has seen it, has been in interaction with other planets.

If anyone tried to contradict the statement that what is true is true independently of our recognizing it as such, he would by his very assertion contradict what he had asserted; he would be in a similar position to the Cretan who said that all Cretans are liars.

Die Gedanken sind weder Dinge der Außenwelt noch Vorstellungen. Ein drittes Reich muß anerkannt werden. Was zu diesem gehört, stimmt mit den Vorstellungen darin überein, daß es nicht mit den Sinnen wahrgenommen werden kann, mit den Dingen aber darin, daß es keines Trägers bedarf, zu dessen Bewußtseinsinhalte es gehört.

In order to produce it [an infinite series] we would need an infinitely long blackboard, an infinite supply of chalk, and an infinite length of time. We may be censured as too cruel for trying to crush so high a flight of the spirit by such a homely objection; but this is no answer.

I compare arithmetic with a tree that unfolds upwards in a multitude of techniques and theorems while the root drives into the depths.

There is more danger of numerical sequences continued indefinitely than of trees growing up to heaven. Each will some time reach its greatest height.

What are numbers? What is the nature of arithmetical truth?

The aim of scientific work is truth. While we internally recognise something as true, we judge, and while we utter judgements, we assert.