What are some reasons to change the air filter? It helps increase fuel efficiency, reduces emissions, and prolongs the life of the engine. Realizing that it is cheap and easy, it doesn't make sense not to. Every 10-15k miles, just pull the old one out and stick a new one in.
A worldview is a bit like an air filter. Everything passes through the filter as you travel the highways of life. And just like the air filter in your car, it is only a matter of time before the filter gets clogged--not with dirt, but with traditions, routines, ideas, emotions, agendas, and experiences. While the purpose of a filter is to keep bad things out, a clogged filter will also prevent good things from getting in. That makes it difficult to engage incoming ideas (decreased fuel efficiency), increases the amount of outgoing bad ides (increased emissions), and will lead to the degeneration of the mind (engine life). Unfortunately, the human tendency is to pride ourselves on the dirt that has accumulated on our filter. It is like a badge of honor in some circles if you can prevent anything at all from getting through.
Just like with my car, it is usually when I am already feeling attacked, that the issue of my dirty filter comes up. It is as if the person with whom I am disagreeing is saying, "Do you also want me to change your worldview?" No way! I can't afford that right now. I will deal with it later. But, does that happen? Of course not. Now, you might be thinking, "Is he seriously saying that I need to change my worldview every so often?" No. I am just suggesting that it needs regular cleaning. One way to clean a dirty filter is to blast it with a pressure washer. That will knock a lot of the gunk off. And if the filter is strong, it will be able to withstand the blast. I think we can do the same with a worldview by regularly reading/listening to those who disagree with us. That doesn't necessarily mean going to the library and checking out the most venomous book from the opposition that you can find (though it might). It might simply mean taking time to honestly consider what that friend who disagrees with you is saying. Apply the pressure and let it knock away anything that doesn't need to be there. If our worldview is sturdy it will be able to withstand the scrutiny. What is more, a regularly cleaned filter will increase your ability to engage incoming ideas, decrease the amount of outgoing bad ideas, and promote the health of the mind.