"That, my friend, is a cow."
"What are you talking about?"
"That animal, right there, is a cow!"
"Wait, you mean that little animal right there?"
"OK, um, why exactly do you think it's a cow?"
"Well, it's all white, like many cows are. It's got a pair of eyes, a body, a head, and a tail, which are all common cow features. And it makes noise, like cows do."
"Yeah, cows do make noise, but they don't normally stretch their wings and quack like ducks."
"Now that you mention it, it is kind of a quacking noise, isn't it? But it's still a cow. I know it."
Sometimes, and rarely it seems, debates will occur where one side must concede that they themselves had a major misconception about a particular point. I'm not talking about a little flub, something misspoken, or the use of something out of context. I'm talking about one of the big ones; a point which should require someone to readjust their entire belief structure, if not cancel it out completely. I'm talking about an idea which, upon further contemplation, leads to that cliché slippery slope on which change is inevitable.
What I've found over the years and across disciplines is that there are very few slippery slopes. They are infinitely more rare than even debate concessions themselves. There is a funny thing that happens in your mind when you are passionate about something enough to debate it, at least to any extent more than casual. You build, and you build, and you build your knowledge up to a mighty mountain, ready to defend your vantage point from a lofty position.
But most of us don't build these perches with smoothly sloping inclines. We're smarter than that. We build terraced slopes. So when we have to concede a critical point, instead of tumbling and sliding down to rock bottom, we just hop down to the next lowest level and think "big deal, I'm still way up on my mountain of knowledge; safe and secure." And often times thereafter we seek for other information to rebuild that lost layer, or go even higher.
In some ways this is good, if not essential, to our survival; especially in our present age. Every day in our times we can encounter more information than people 5000 years ago would have seen in a year, or maybe even in their entire lives. This information brew is filled with intoxicating tidbits which support, refute, or append to our world view; and we have the difficulty of trying to sort out the truth without getting inebriated. The information alone is more than enough to handle, but throw in our own minds "spiking the punch" with 140 proof Confirmation Bias and it becomes a miracle if we can speak the truth without slurring our words.
It's not easy. It isn't. So we shouldn't be surprised that people cling to ideas which we ourselves have deemed as wrong. And we shouldn't be surprised that when we do manage to score a major point in an argument that the other person is only slightly humbled but is still standing as firmly as ever on the next terrace of their belief.
I understand this, but it doesn't make it any less frustrating! :-p
For a related but different perspective, check out Sabio Lantz's excellent post on "Busting Beliefs."