Intelligence is not a personality trait

Ten years ago, few people thought that Elon Musk was an idiot. Yes, perceptive observers could probably tell that there was more P.T. Barnum about him than Nikola Tesla. But even P.T. Barnum was shrewd. Musk may not have been a genius, but as a business person, he was apparently a decent – if eccentric – one. That perception is now shattered.

Robert F. Kennedy, Jr.'s public perception has gone through a similar shift. As an environmental lawyer, he wielded scientific findings to hold large companies accountable for their misdeeds. Now he's an anti-vaccine conspiracy theorist.

It might appear that Elon Musk and RFK, Jr. became different people, but the reality is that the public came to view them differently because time took its course. New evidence – of their thinking and decision-making skills – made us gravitate toward new explanations that explain both prior and current behavior. RFK Jr., isn't a science-in-the-public-interest guy; he's an anti-corporate guy, who uses scientific findings only when convenient to further anti-corporate ends. Musk isn't a brilliant business person – otherwise, he wouldn't single-handedly torpedo Twitter's value – he's petulant and erratic. The idea that he's secretly playing 4D chess is laughable.

When these shifts in public perception occur, there's an instinct to say, "I told you so." This person was always this way or that way. But the problem isn't necessarily that we pegged them wrong – it's that we pegged them too early.

It's hard to know whether someone is smart. It's especially hard as a member of the public who gets occasional updates about famous people and the decisions they're making. We're outsiders – it's hard to tell who made which decisions and under what basis they were made. And often the ramifications of these decisions will not occur for years. What seems smart now may seem dumb five years from now. And vice versa.

Add to that the complex brew of factors that go into whether such decisions are "successful", and it becomes nearly impossible to distinguish a shrewd business decision from a pea-brained one; or a thoughtful thought leader from a thoughtless one.

It's easy to tell that Obama is professorial or that Musk is a showman. But these are personality traits – or, more precisely, public personas. These words describe how people appear to be. They don't say much about the quality of the decisions that those people will make.

It's one thing to say that someone is good at chess or good at basketball or good at making bespoke signs for their child's Lego buildings. These are specific skills, occurring in well-defined contexts, with lots of evidence about the skill levels.

But intelligence unfolds across a wide variety of time periods and contexts. We can be very smart in some contexts and very dumb in others. And there are many axes around which people act. Without clearly understanding the decision-maker's goals, it's impossible to judge the wisdom of any particular decision.

In short: it is not immediately obvious that someone is smart or dumb. It's not immediately obvious that an idea is good or bad. Sometimes, we have to reserve judgment and just wait and see.