I’m currently reading Robert Skidelsky’s single-volume biography of John Maynard Keynes. Keynes was one of the most remarkable economist, thinkers and writers of the 20th century. His letters and books are full of witty remarks and unique turns of phrase. Here’s some examples:

• “But this long run is a misleading guide to current affairs. In the long run we are all dead.”
• “Words ought to be a little wild, for they are the assault of thoughts on the unthinking.”
• “If you owe your bank a hundred pounds, you have a problem. But if you owe a million, it has.”
• “There is no harm in being sometimes wrong — especially if one is promptly found out.”
• “Markets can remain irrational longer than you can remain solvent.”
• “Practical men who believe themselves to be quite exempt from any intellectual influence, are usually the slaves of some defunct economist. Madmen in authority, who hear voices in the air, are distilling their frenzy from some academic scribbler of a few years back.”
• “The difficulty lies not so much in developing new ideas as in escaping from old ones.”

One of my favorite Keynes quotes involves his reply to a criticism of him for changing his mind on a policy position he’d taken in the past. In a sharp and arresting retort Keynes replied, “When the facts change, I change my mind. What do you do, sir?”

Keynes was insinuating two things in this remark: One, changing our mind is naturally what we do as we become more educated on a subject over time. That’s just common sense old chap! And two, “What do you do, sir?” is Keynes’s way of asking his critic if he’s one of those people who prefers the “hobgoblin” of consistency over intellectual integrity. A question we should all be asking ourselves.

Changing our mind is something honest and thoughtful people must sometimes do. Changing our mind about various ideas and beliefs is something we should be doing over our lifetimes as we experience and learn. It’s the true sign of a mature mind. This is especially true in politics, where many people’s beliefs are based more on gut and party than a thoughtful evaluation of people, policy, facts, and sincere interests. “Life is,” as James Barrie said, “one long lesson in humility.”

The safest course is to always remain humble about knowledge and certainty while remaining open minded and intellectually curious.