Hold firm your beliefs, let your opinions change

version of this essay was published as part of my monthly newsletter several weeks back. Find other archives and join here to get updates like this first.

Hippasus was a student of the Greek philosopher-mathematician Pythagoras 2,500 years ago.

Pythagoras, whom you may know for popularizing a theorem that is today named for him, taught that all numbers could be expressed as a ratio of two whole numbers. This seems obviously wrong to us today.

Turns out it seemed wrong to Hippasus too. He is credited with first defining irrational numbers and disproving Pythagoras. It caused an intellectual split. In the midst of a passionate debate at sea, as the legend goes, Hippasus was thrown off a ship and drowned.

Most of us have probably wanted to throw someone off a boat for entirely upending a belief of ours. It’s a necessary, if frustrating, act.

Life comes so fast that it’s understandable to stick to what we already believe.

Mostly, we operate with two kinds of facts: those that are effectively fixed (the height of Mount Everest*) and those we know are constantly changing (what the temperature is outside). We view our core beliefs mostly in the fixed category.

But we ought to keep in mind a third category: slow-changing facts, like, say, the population of a city. Back in 2010, a Boston Globe columnist called a slow-changing truth a mesofact. The goal of giving them a name was to awaken us to be more accustomed to that changing. I believe our opinions should reside in this category too.

With new information ought to come an acceptance than our opinions might change. This could be freeing — but we are increasingly paralyzed by fear of what an opinion might do to us. Two-thirds of Americans report they keep opinions private  that they fear to share publicly. 

Personally I’m puzzled by how quickly and vehemently so many people seem can establish and defend an opinion on such a wide range of issues. I think often of what British philosopher Bertrand Russel wrote: “One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision.”

Or as Yeats put it: “The best lack all conviction, while the worst are filled with passionate intensity.” It’s one reason job interviews are so fraught: the interviewees who appear most confident may not be. (Tip: avoid candidates who use “always” and “never” and gravitate to those who actually teach you something)

We have some understanding of why we change our mind. It’s a lot easier if we treat an opinion like something that might evolve over time. The hard part is it seems our resistance to change our mind is a feature of our hypersociability, not a bug. It is quite truly human nature to develop an opinion because of a group of people we associate with, and then view that opinion as fixed as the height of Mount Everest. Reason helps us stay within the in-group, which is an awfully good way to stay alive. If you offer unwelcome truths, you might get yourself drowned.