The reason why any one refuses his assent to your opinion, or his aid to your benevolent design, is in you: he refuses to accept you as a bringer of truth, because, though you think you have it, he feels that you have it not. You have not given him the authentic sign.
I know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives.
The logic now in use serves rather to fix and give stability to the errors which have their foundation in commonly received notions than to help the search for truth. So it does more harm than good.