Are brave people brave because they are better at controlling their own fears? Or are they brave because they feel less fear in the first place?
It may seem like an idle and abstract question, but the way we judge and think of people’s character depends on the answer to that question.
And it applies to virtually every personality trait. Are we more melancholic than our jolly friend because we give up more easily to sad thoughts? Or do we experience sad thoughts more intensively?
What intrigues me about this question is that we can never really answer it. In order to compare two people’s feelings (let’s say, the fear of approaching a stranger) we would have to quantify those feelings first. But how do we do it? Even if we ask each person to assign a number to their fear, what we get is always a relative measure. They could both come up with “4 out of 10”, but if the first person is twice as sensitive as the other then his/her “4” is by definition an “8” in the other person’s scale. Our internal thermometers might have completely different calibrations but we never find out because we can only compare the numbers we read on them.
It seems to me we never really acknowledge this ambiguity. We are hardwired to see different characters as different attitudes towards the same quality of experience. It’s a framework that does work in the physical world: if you can lift 50 kg and I lift 25 kg, you’re twice as strong as me in an unambiguous way. The external factor (the weight) can be objectively quantified and what’s left to compare is our bodies’ ability to cope with it.
Internal states do not work like that. And we now have plenty of evidence that suggests this. For example, we know that changes in chemicals in the brain can drastically change the way people experience their life (bipolarism, clinical depression). And we know that traits like introversion and extroversion are closely linked to the degree of reactivity to external stimuli¹.
The consequences of this peculiar arithmetic of feelings are meaningful. If introverts are more sensitive than extroverts, for example, then their being less social has nothing to do with them being less interested in people. It’s just that they “experience” people much more than others, satisfying their social needs (identical to everyone else’s) much faster.
It is a new perspective that would make us less judgemental with other people (and ourselves). We should simply acknowledge that we do not know what each other’s thermometers measure.
 More details in the great book “Quiet” by Susan Cain, highly recommended.