|A priori: something that we can know without prior (empirical) investigation. Is the inventory of a priori certainties purely logical? Is a priori knowledge always necessary?|
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Necessary/not a priori: E.g. Goldbach’s conjecture: If it will turn out, then by necessity.
A priori/not necessary: E.g. determining the reference of the term "one meter": it is possible to know a priori that the length of this stick is one meter, and this would not be seen as a necessary truth.
Difference: a priori/necessary: Kripke: you could empirically discover the essence (e.g. water = H20).
Name und Notwendigkeit Frankfurt 1981
S. A. Kripke
Outline of a Theory of Truth (1975)
Recent Essays on Truth and the Liar Paradox, R. L. Martin (Hg), Oxford/NY 1984