Straight From the Source
Extending the See-Saw Metaphor from before:
Our evaluation of additional evidence is always conditioned by our previous beliefs and knowledge; our ideas about what the world is are the glass full of subtle colors and astigmatisms through which we perceive new experiences.
When the new data contradicts things we believe we already know, we often reject the data as flawed. But that rules out the possibility of recognizing a false belief and updating it. It’s a natural human tendency to protect our beliefs simply because they’re ours and we hold them. Staying with the familiar is easy and comforting, but doing so traps us in a rut of our own creation, forever going over the same ground.
If we refuse to give our preconceptions more weight than our perceptions, though, we’re faced with a problem. Given two incompatible statements, how do we choose between them? We can try to keep both in our minds as contingencies until we learn more, but that just postpones the issue. Without criteria for judging which statement to accept and which to reject, it leads to a infinite iteration that provides no conclusion.
The simple truth, and one which most of us would acknowledge as self-evident if we took the time to think about it, is that some data is more ontologically fundamental than others. I don’t like that phrase, but it’s the best one I can find to fit the meaning. We can use our understanding of reality to interpret and possibly dispose of evidence contrary to it, but ultimately our model is just a model. The evidence arises from the thing we’re trying to understand, while our understanding comes from a middleman.
This basic point is often not put into practice, though. It’s so easy to disregard reality and pay attention only to the model of it in our heads – what sounds like an absurdity is how most people get through their lives.