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Comment by jotakami | Hacker News Reader

There’s a difference between “one factor that explains everything” and a dominant factor that explains most of the variation.

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I just doubt that in many cases there is a dominant factor that explains most but I think that instead there are often several factors of more or less equal importance. We made that mistake already in nutrition ("fat is the main problem") and it caused decades of problems. The proportion of these factors is also highly individual.

Why do you believe that it’s more likely for several factors to have roughly equal importance than for one factor to be the most important?

As an aside, the mistake in nutrition was simply that it wasn’t true. And it also wasn’t a “mistake,” it was a lie that the sugar industry paid to spread.

the mistake in nutrition was to think that fat is the dominant factor. In reality, if you eat too much sugar, too much fat, not enough vitamins, exercise too little or too much, don't take care of your mental health, drink too much caffeine, smoke, drink too little or too much or just have bad genes you have a chance to get health problems. There is no dominant single factor you can focus on to be healthy for sure.

>Why do you believe that it’s more likely for several factors to have roughly equal importance than for one factor to be the most important?

if you pick n numbers at random, it's not likely that one of them is bigger than the half of their sum.

What if n=1 ? :)

That really depends on the distribution of said numbers. You're probably assuming uniform distribution, but there are power law distributions like wealth where the 26 richest people own as much as the bottom 3.8 billion combined.

to be honest, I don't know much about probability.

but my intuition says that if you pick all variables from the same distribution, this should still hold.

At first, we don't know anything about the factors, so they are assigned a random importance. or am I missing something?

You don't accept the possibility this could be true?

What's missing here are facts.

To dismiss something based on something anecdotally unrelated seems short-sighted.

Doubt =/= dismissal

> dominant factor that explains most of the variation.

A dominant factor can also only account for less than half of an explanation if there are enough factors. E.g. Peer group is 40%, parents are 30%, teachers are 20%, TV/videogames/groups-seen-but-not-interacting-directly-with 10%. Here peer groups would still be dominating but parents and teachers are significant factors as well. These percentages are close enough that it would be ridiculous to just focus on one (or even the first two alone).

For all X, if you study the effects of X on a complex system hard enough, it will look like X is the dominant factor that explains most of the variation.

I happen to believe peer groups are really important. But other things are important, too, including the adults.

Remove all the middle-aged and older men from a city, but still provide other necessities, and you'll see some terrible outcomes. (This is true in other species as well, like elephants where older males are hunted for tusks.)

Do you sometimes pick up a different child from kindergarten just for a bit of variety in complexion and looks at the dinner table, since that child will be essentially indistinguishable from your son in development and personality anyway, so you might as well?

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