What You Believe Changes What You See

I just heard someone say, "If your theory doesn't match the facts, you need to change your theory." This good-sense advice may seem obvious, but people often do just the opposite.

Theory becomes belief, and belief is perceived as truth. When it doesn't fit the facts, rather than admit that what we believe isn't true, and change our theory to fit the facts, we prefer to twist our interpretation of the facts to fit our theory, which has now become dogma.

It is clear that this happens all too often in politics, religion, history, economics, and many kinds of research.