4.1 Bolzano and Frege—The rejection of psychologism in logic—Can there be just "signs of signs"?—Frege's notions of "sense", "reference" and "representation"—Our images of things as psychological—Relativity of any representations: their problematic subjectivity. 4.2 The objectivity of Frege's "thoughts"—Importance of context—Truth-values and verification as conditions of knowledge—True and false judgments. 4.3 Cases of "indirect reference": truth and falsity of our beliefs—Frege on intersubjectivity—The social nature of language—The intrinsic non-truth of our thoughts—Inevitability of admitting a reality in itself that is independent from subjective perspectives—Frege's "third realm": objectivity as non-actual—The bankruptcy of correspondism—Popper, Dummett and Soames on the dangers of metaphysical realism or Platonism—Analytic and synthetic truths: the timelessness of both timeless and temporal thoughts—Pursuing solid epistemic standards not only for context-independent but also for context-dependent knowledge.