When one attends to any of one's beliefs, one must regard it as believed for sufficient or adequate reasons. [1]
I'll not get into the full development of Adler's evidentialist ethics of belief (which is interesting). Instead, I'll just note that this is a pretty stringent requirement. The evidentialists I have the privilege of working with at the University of Rochester don't affirm this principle, for example, Earl Conee argued against it in his review of the book. I don't know where I stand on it. There are days that I think it's true, other days that I think it's not.
So, it was surprising when combing through Reid's conception of evidence in preparation for a seminar, that I ran across the following:
We give the name of evidence to whatever is a ground of belief. To believe without evidence is a weakness which every man is concerned to avoid, and which every man wishes to avoid. Nor is it in a man's power to believe anything longer than he thinks he has evidence. [2]
Some externalists, Plantinga not the least among them, have taken aid and comfort from Reid. It's not surprising that Plantinga finds much to like in Reid, his proper functionalism sounds at home among Reid's frequent references to "original constitution" and to being "fitted by nature" to believe in various ways. But in the above quote, it's interesting that Reid sounds like a strident evidentialist.
'Evidence' may be equivocal here, though. I'm still feeling out what Reid means by evidence. He does sometimes sound as though evidence is all mental (only a few paragraphs later, in fact). But in the Inquiry into the Human Mind Reid seems to say that some appearances are non-mental (though it's hard to find them in the physical world), and appearances seem likely to count as evidence. But at any rate, it's interesting to find an externalist muse saying something that sounds stridently evidentialist.
[1] Jonathan Adler, Belief's Own Ethics, (MIT: 2002), 26.
[2] Thomas Reid, Essays on the Intellectual Powers of Man, II.20.
