I have certainly no right to say that they purposely shut their eyes to such arguments.

I ought rather to doubt the validity of them, when neglected by such men, however forcibly their truth may strike my own mind.

Yet in this respect it must be acknowledged that we are all of us too prone to err.

If I saw a glass of wine repeatedly presented to a man, and he took no notice of it, I should be apt to think that he was blind or uncivil.

A juster philosophy might teach me rather to think that my eyes deceived me and that the offer was not really what I conceived it to be.
In entering upon the argument I must premise that I put out of the question, at present, all mere conjectures, that is, all suppositions, the probable realization of which cannot be inferred upon any just philosophical grounds.