Indubitable

Change is one thing, progress is another. "Change" is scientific, "progress" is ethical; change is indubitable, whereas progress is a matter of controversy.

Philosophy is a science, and as such has no articles of faith; accordingly, in it nothing can be assumed as existing except what is either positively given empirically, or demonstrated through indubitable conclusions.

The indubitable effect of the potion convinced many nonbelievers.

If we build logically upwards from a few indubitables, the whole system must remain correct.