Very little time goes by between my encounters with the request to keep an open mind. It has come to the point where I find myself wary of those who say it, and I wonder why they are asking me to keep an open mind. What, after all, does that really mean?

I get the impression that an open mind, in the opinion of the general populace, means a lack of judgment. “Whatever ideas you may encounter, don’t judge them. Just accept them. Don’t be so judgmental. Everyone has a right to his opinion, and no one is in any place to tell someone else that he is wrong. The only time it is okay to tell people that they are wrong is when they are telling someone that they are wrong. Ideas are neither true nor false; it’s all up to the individual.”

Such seems to be the manifesto behind most encouragement to keep an open mind. But G.K. Chesterton warns us:

Millions of mild black-coated men call themselves sane and sensible merely because they always catch the fashionable insanity, because they are hurried into madness after madness by the maelstrom of the world.

Is the current idea about open-mindedness just another one of these fashionable insanities? It might be worth it, then, to not be so open-minded about this modern, non-judgmental view of open-mindedness. After all, Chesterton also wrote, “Be careful not to be so open-minded that your brains fall out.” 

What does it really mean to have an open mind? It is an attitude or state of a mind, a state of receptivity and inquiry. And what is a mind? It is an intellect, an abstract power of the human person to form, receive, synthesize and judge ideas. The ultimate good of the mind is truth, the knowledge of reality, and in the end, God himself. The job of the mind is to judge ideas as either true or false, matching with reality or not. As James Schall wrote, “A mind that cannot or will not make an affirmation or judgement is not a mind.” 

Of course it is necessary to refrain from making a judgment without sufficient evidence or information, but a person who simply refuses to make any judgment, whose mind remains perpetually open, is giving up the very thing that makes him human: his mind. Schall’s view of the duty of the mind is directly in opposition to the sense created by modern admonitions to keep an open mind.

The purpose of an open mind, then, is not simply to let in all ideas without judging them, but to allow the idea to fully enter the mind so that it can be judged well. It is an error of mind to never judge an idea. It is also an error to judge an idea before it is fully understood. In order for the mind to judge well, it must have sufficient information. By analogy, the mouth must be opened wide enough and long enough to allow food to enter, but at the same time, the mouth must bite down and chew the food so that it can enter and nourish the body. So, too, the mind must be open to receive ideas, but it must also close on them to draw out and separate what is true and false in them.

One of the most helpful examples of proper open-mindedness is the philosophy of the Middle Ages, and St. Thomas Aquinas in particular. He quotes freely from pagan, Jewish, Muslim and Christian sources. He clearly took the time to thoroughly examine and understand these other thinkers because truth is truth no matter where it comes from. At the same time, he subjected all of those thoughts to relentless rational analysis. Thomas Aquinas was certainly a man with a proper amount of open-mindedness.

Examples of minds that did not stay open long enough are the modern philosophers, beginning with Descartes. In general, they threw out all the thinkers before them because they either misunderstood or ignored them. Unfortunately, it is not possible to find among the modern philosophers a rigorous understanding of the thinkers who went before them. If the thinkers of the Middle Ages prided themselves on being dwarves standing on the shoulders of giants, the modern era thinkers prided themselves on being giant-slayers so they could retain their diminutive height.

The important thing, then, is to keep an open mind for the right amount of time. If one keeps an open mind indefinitely, then he refuses to use his mind and so loses it. That is when the brains fall out. If the mind is not opened at all, it becomes cramped and mean from lack of nutrition. So, keep an open mind, and shut it when necessary.