confirm, corroborate, substantiate, verify etc.Evidence [On one side.], settle the question, reduce to demonstration, set the question at rest. make out, make out a case
prove one's point, have the best of the argument
draw a conclusion etc.(judge)Judgment [Conclusion.]. follow, follow of course, follow as a matter of course, follow necessarily
stand to reason
hold good, hold water. convince, persuade (belief)Belief.
Adjectives
demonstrating etc. v., demonstrative, demonstrable
probative, unanswerable, conclusive
apodictic, apodeictic, apodeictical
irresistible, irrefutable, irrefragable
necessary. categorical, decisive, crucial. demonstrated etc. v.