doubtful proof

And we questioned the mummy of Oigos, to learn if he had perceived in the room, with such senses as are peculiar to the dead, the sure token or doubtful proof of a presence undescried by us the living.

Nay, my good friend, do not say that; there have been, as there always will be, flights and pursuits of which no account can be given, and therefore we cannot say that victory or defeat in battle affords more than a doubtful proof of the goodness or badness of institutions.