We are usually convinced more easily by reasons we have found ourselves than by those which have occurred to others.
Pascal identifies something subtler than mere stubbornness—he's describing the architecture of conviction itself. When you arrive at a conclusion through your own thinking, you've built a mental scaffold supporting it; when someone hands you their reasoning, you're standing on their scaffold, which feels foreign to your feet. A parent who finally grasps why their teenager needs autonomy through their own fumbling experiments will enforce that boundary far more consistently than one who merely accepts a parenting book's argument, no matter how eloquent. The implication cuts both ways: it explains why argument alone rarely changes minds, but it also suggests that the most generous thing we can do isn't always to persuade more forcefully—sometimes it's to create the conditions where others discover the truth themselves.