Such principles, however, are not trivial to the philosopher, for they show that we may have indubitable knowledge which is in no way derived from objects of sense.
The intention, however, was indubitable; and whether it was that his manners had in general so little gallantry, or however else it happened, but she thought nothing became him more.
For, once more, it is indubitable that the sum of the net increments of the wealth of individuals must be exactly equal to the aggregate net increment of the wealth of the community.
At this point Descartes says that " if I am fortunate enough to find a single truth which is certain and indubitable, " that will suffice to reverse doubt and establish a philosophy.
Our knowledge of such relations, though it requires more power of abstraction than is required for perceiving the qualities of sense-data, appears to be equally immediate, and (at least in some cases) equally indubitable.