1. incontestable because of having been demonstrated or proved to be demonstrable.
2. Logic. (of a proposition) necessarily true or logically certain.
Also, ap·o·deic·tic /ˌæpəˈdaɪktɪk/ Show Spelled, ap·o·dic·ti·cal.
1645–55; < L apodīcticus < Gk apodeiktikós proving fully. See apo-, deictic
ap·o·dic·ti·cal·ly, ap·o·deic·ti·cal·ly, adverb
The fact is, I am dogmatic. I do have unwavering faith in a set of claims. I may affect suspicion of them, but FAPP, I use them as apodictic truths.
Source: Three Pound Brain.