Ultimately, we think that such arguments lead to their conclusions because we accept certain logical principles—such as the law of non-contradiction, or modus ponens—which appear to us to be self-evident. But to say that such principles are self-evident is just to say that we cannot help but accept them. It is not to offer any non-circular justification of those principles. But the irresistibility of a belief is a very good indicator, Reid thinks, that we hold that belief merely because of the w