You say that faith is a gift; this is perhaps the most correct thing that can be said about it. - Carl Friedrich Gauss

Letter to Bessel (1826), quoted in Dunnington, G. Waldo. "Gauss, His Disquisitiones Arithmeticae, and His Contemporaries in the Institut de France." National Mathematics Magazine 9.7 (1935): 187-192.

One cannot reduce to concepts the distinction between two systems of three straight lines each (directed lines, of which the one system points forward, upward to the right, the other forward, upward to the left) but one can only demonstrate by holding to actually present spatial things. Two minds cannot reach agreement about it unless their views connect up with one and the same system present in the real world

Das Ergebnis habe ich schon, jetzt brauche ich nur noch den Weg, der zu ihm führt.