kb/data/en.wikipedia.org/wiki/Bernard_Bolzano-3.md

title	chunk	source	category	tags	date_saved	instance
Bernard Bolzano	4/5	https://en.wikipedia.org/wiki/Bernard_Bolzano	reference	science, encyclopedia	2026-05-05T16:20:03.001000+00:00	kb-cron

==== Truth ==== Bolzano distinguishes five meanings the words true and truth have in common usage, all of which Bolzano takes to be unproblematic. The meanings are listed in order of properness: I. Abstract objective meaning: Truth signifies an attribute that may apply to a proposition, primarily to a proposition in itself, namely the attribute on the basis of which the proposition expresses something that in reality is as is expressed. Antonyms: falsity, falseness, falsehood. II. Concrete objective meaning: (a) Truth signifies a proposition that has the attribute truth in the abstract objective meaning. Antonym: (a) falsehood. III. Subjective meaning: (a) Truth signifies a correct judgment. Antonym: (a) mistake. IV. Collective meaning: Truth signifies a body or multiplicity true propositions or judgments (e.g. the biblical truth). V. Improper meaning: True signifies that some object is in reality what some denomination states it to be. (e.g. the true God). Antonyms: false, unreal, illusory. Bolzano's primary concern is with the concrete objective meaning: with concrete objective truths or truths in themselves. All truths in themselves are a kind of propositions in themselves. They do not exist, i.e. they are not spatiotemporally located as thought and spoken propositions are. However, certain propositions have the attribute of being a truth in itself. Being a thought proposition is not a part of the concept of a truth in itself, notwithstanding the fact that, given God's omniscience, all truths in themselves are also thought truths. The concepts 'truth in itself' and 'thought truth' are interchangeable, as they apply to the same objects, but they are not identical. Bolzano offers as the correct definition of (abstract objective) truth: a proposition is true if it expresses something that applies to its object. The correct definition of a (concrete objective) truth must thus be: a truth is a proposition that expresses something that applies to its object. This definition applies to truths in themselves, rather than to thought or known truths, as none of the concepts figuring in this definition are subordinate to a concept of something mental or known. Bolzano proves in §§31–32 of his Wissenschaftslehre three things: There is at least one truth in itself (concrete objective meaning):

1. There are no true propositions (assumption)

2. 1. is a proposition (obvious)
3. 1. is true (assumed) and false (because of 1.)
4. 1. is self-contradictory (because of 3.)
5. 1. is false (because of 4.)

6. There is at least one true proposition (because of 1. and 5.) B. There is more than one truth in itself:

7. There is only one truth in itself, namely A is B (assumption)

8. A is B is a truth in itself (because of 7.)

9. There are no other truths in themselves apart from A is B (because of 7.)

10. 9. is a true proposition/ a truth in itself (because of 7.)

11. There are two truths in themselves (because of 8. and 10.)

12. There is more than one truth in itself (because of 11.) C. There are infinitely many truths in themselves:

13. There are only n truths in themselves, namely A is B .... Y is Z (assumption)

14. A is B .... Y is Z are n truths in themselves (because of 13.)

15. There are no other truths apart from A is B .... Y is Z (because of 13.)

16. 15. is a true proposition/ a truth in itself (because of 13.)

17. There are n+1 truths in themselves (because of 14. and 16.)

18. Steps 1 to 5 can be repeated for n+1, which results in n+2 truths and so on endlessly (because n is a variable)

19. There are infinitely many truths in themselves (because of 18.)

==== Judgments and cognitions ==== A known truth has as its parts (Bestandteile) a truth in itself and a judgment (Bolzano, Wissenschaftslehre §26). A judgment is a thought which states a true proposition. In judging (at least when the matter of the judgment is a true proposition), the idea of an object is being connected in a certain way with the idea of a characteristic (§ 23). In true judgments, the relation between the idea of the object and the idea of the characteristic is an actual/existent relation (§28). Every judgment has as its matter a proposition, which is either true or false. Every judgment exists, but not "für sich". Judgments, namely, in contrast with propositions in themselves, are dependent on subjective mental activity. Not every mental activity, though, has to be a judgment; recall that all judgments have as matter propositions, and hence all judgments need to be either true or false. Mere presentations or thoughts are examples of mental activities which do not necessarily need to be stated (behaupten), and so are not judgments (§ 34). Judgments that have as its matter true propositions can be called cognitions (§36). Cognitions are also dependent on the subject, and so, opposed to truths in themselves, cognitions do permit degrees; a proposition can be more or less known, but it cannot be more or less true. Every cognition implies necessarily a judgment, but not every judgment is necessarily cognition, because there are also judgments that are not true. Bolzano maintains that there are no such things as false cognitions, only false judgments (§34).

== Philosophical legacy == Bolzano came to be surrounded by a circle of friends and pupils who spread his thoughts about (the so-called Bolzano Circle), but the effect of his thought on philosophy initially seemed destined to be slight. Alois Höfler (1853–1922), a former student of Franz Brentano and Alexius Meinong, who subsequently become professor of pedagogy at the University of Vienna, created the "missing link between the Vienna Circle and the Bolzano tradition in Austria." Bolzano's work was rediscovered, however, by Edmund Husserl and Kazimierz Twardowski, both students of Brentano. Through them, Bolzano became a formative influence on both phenomenology and analytic philosophy.