In the world of statistical inference, a “prior” refers to the beliefs we have about a particular value before we have all the data.

In practice, this means that if we’ve done all the calculations required to ship a batch of a particular product from warehouses to grocery stores, but then discover that the product actually weights three ounces more than we were originally told, it’s important that we go back through all of our calculations and change them based on this updated information.

It may be that some of our original plans will still stand, but it could also be the case that some of the boxes won’t safely hold the product as we assumed they would, or the trucks carrying pallets of the product won’t have enough fuel to get from Point A to Point B, because the original calculations, though only off by a little bit, can have repercussions that add up, over time and on scale.

In a more metaphorical sense, updating one’s priors generally means updating not just the behavior associated with a particular assumption when new information becomes available, but also reassessing the totality of all behaviors—past, present, and future—associated with that outdated understanding.

This means not just changing our minds about a specific political concept as we learn more about the world, but figuring out why our minds have been changed, what that means for the underlying beliefs from which we derived our earlier opinions, and then tracing those beliefs to see what other decisions we’ve made based on them—and then changing those, too, if possible.

This process is seldom a pleasant or simple one.

It can be difficult enough admitting to ourselves that we’ve perhaps been duped, been misinformed, or been wrong about something—even if only in the subjective and not absolute sense.

It’s awkward to think that we’ve maybe done things that clash with how we perceive ourselves to be, as people, and this can be true even if we acted in alignment with our beliefs at the time; the misalignment only existing in retrospect, through the lens of our new beliefs or knowledge.

Part of this discomfort stems from a sort of embarrassment: I can’t believe I didn’t arrive at this clearly better, more me-shaped belief, sooner. I can’t believe I behaved in that way, thought those things, made those decisions based on information that’s clearly wrong, ideas that are clearly false, and so on.

It’s also uncomfortable, though, because it implies that the same could happen again in the future. There’s a chance—a very decent chance—that we could someday look back at who we are today, and the decisions we’re making, the things we’re doing, and marvel at our ignorance, our lack of perspective and inability to see the truth that has become so evident to our future selves.

Updating a perceptual prior, in this context, means being willing to change not just how we think about one thing, but how we think about everything.

It means not just being willing to change our minds, but being willing to trace that change inward and outward, catalyzing a cascade of adjustments to our thinking, our behaviors, our habits and reflexes and biases, in an attempt to bring ourselves into better alignment with what we believe and know, now.

Keeping our priors malleable in this way is no guarantee that we’ll always get it right, nor that we’ll ever be able to say with absolute certainty that the beliefs we hold today are the beliefs we’ll hold for the rest of our lives. We’ll continue to feel foolish and embarrassed, at times, and that’s okay—that means we’re growing.

What such attention and effort grants us is the knowledge that, if we’re persistent and humble, our current set of understandings and beliefs can be woven throughout our lives—including our behaviors, not just our theories—which makes it more likely that we’ll, at any given moment, act in alignment with the most up-to-date version of who we are, rather than falling into outdated habits and patterns of thinking.

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