|Necessity, philosophy: different kinds of necessity are distinguished, differing in their strength. For example, physical, logical or metaphysical necessity. See also necessity de dicto, necessity de re.|
Books on Amazon
Necessity/necessary/Wittgenstein: a necessity in the world corresponds to an arbitrary rule in the language.
Necessity/Wittgenstein: not in objects, only in terms - not with hues (that necessarily there is a hue in between) but in the representing system (> agreement).
Vorlesungen 1930-35 Frankfurt 1989
Das Blaue Buch - Eine Philosophische Betrachtung Frankfurt 1984
Tractatus Logico Philosophicus Frankfurt/M 1960