The Argument
I got into it with family a while back about protein. My position was that Indian diets are protein-deficient. I think this traces back to how much less meat and fish people eat now compared to a few generations back. Their position was different. They said Indians have thrived on a carb-heavy diet for millennia, so the sudden alarm about protein doesn’t make sense. I pushed back. It’s a different population under different conditions, I said. The loss of animal protein over time is the real gap. We went around a few more times. At some point it started going in a loop. I had said what I had to say. I didn’t agree with anything they were saying. Continuing wasn’t going to produce anything. So I said something like “fine, whatever,” and let it go.
I still think I was right. Here’s what I noticed afterward. I stopped arguing, but nothing in my head actually changed. I gave up the argument without giving up the belief. That reminded me of the backfire effect, the familiar claim that correcting someone’s facts makes them dig in harder instead of updating. People usually study this through politics. But the research doesn’t really back the popular version of it. Political scientists Thomas Wood and Ethan Porter tested it directly. They looked at 52 issues and over ten thousand people. They picked the most polarizing topics they could find. Even then, people mostly updated on the facts, including facts that hurt their own side. So that made me question myself even more. If correction usually works, why didn’t either side correct themselves?
Two Stories, No Facts
The obvious answer is that there weren’t any facts in the argument to update on. Not mine, not theirs. I don’t have real data on Indian protein intake across generations. I doubt they had real data on historical diets either. We were each running a story and treating it like truth. A writer named Dan Williams studies this kind of disagreement. One of his examples stuck with me. Two people can agree completely that inflation went up 5 percent. They can still explain it through opposite stories, a supply shock or a policy failure. They never actually disagree on the number. Ours didn’t even have a number. Just two stories. And an argument that felt exactly like a fight about facts, the whole time it was happening.
There’s a related idea that’s even older. Researchers Hugo Mercier and Dan Sperber have argued that human reasoning may not have evolved mainly to help us find things out. It may have evolved to help us win arguments and stay credible while doing it. I ran into this idea through a blog post by economist Robin Hanson. If they’re roughly right, I may not have been reasoning badly at the table. I was using reasoning to defend a position instead of investigate one. It’s the same instinct at work when an idea only lands once you swap out the example carrying it, the argument didn’t change, just how defensible it felt.
What I Actually Know
Here’s where I have to be harder on myself than the argument required. Part of why I don’t take a lot of unsolicited advice, on diet, exercise, what to do about a cold, is that I’ve been tracking this stuff for years. I log calories. I track workouts. I weigh myself. I count steps. Over time I’ve built up a rough sense of how my body responds to things. More sleep. Less sugar. A harder training block. When someone offers me generic advice, I usually don’t take it. I think my own tracked history is better evidence than their guess.
But it’s weaker evidence than it feels like from the inside. Years of tracked calories and weights isn’t a controlled experiment. It’s one person, in one life. Some symptoms just go away on their own, no matter what I do. Some patterns would have evened out anyway, whether I noticed them or not. And my memory is much better at holding onto the times something “worked” than the times it didn’t. It’s still evidence. It just doesn’t prove everything I want it to prove. “This worked” and “I know this works” aren’t quite the same claim, even when they come from the same numbers.
And even if it were airtight, it still wouldn’t touch the actual claim I made at the table. I’ve never had a blood panel that measured anything protein-specific. Even if I had, that’s still just my body, right now. The claim I was defending is about a whole population, across generations, compared to a diet almost nobody eats anymore. Nothing about my own body can settle that. What could settle it is something like old nutrition surveys, or historical records of what people actually ate. Not my step count. Not how I feel after a workout.
What Would Actually Change My Mind
I genuinely don’t know what would move me off the protein thing. I can’t point to the specific evidence that would do it. That’s a strange thing to notice about a belief I was willing to argue for at a dinner table. It’s not another round of the same argument. I’ve had that round more than once, and conceding it out loud clearly wasn’t it. It’s not my own numbers either, for the reasons above. Maybe actual data on the thing I was actually claiming, if I ever went looking for it, which I haven’t.
I don’t think this resolves into one clean lesson. Wood and Porter’s finding suggests facts probably do move people more than I assumed. That means it’s possible the protein argument was winnable by evidence. I just never supplied any. Williams’s point about rival stories suggests something more limited. Evidence doesn’t interpret itself. Two people can still disagree about what a fact means, even after they agree on the fact itself. Both of those things might be true at once. Neither one fully explains what happened at the table. The simplest version is probably just this. Two people confidently argued about something neither of us had actually researched. Both of us walked away still convinced.