How do we know red is red?

When I was just a whee little boy this used to trouble me, and it’s still something of a conundrum.

How do we know that colors are not just randomly assigned by the brain?

For example, the color I see as red might actually look like blue in your head, but since you have always seen the color red assigned as blue by your brain, our observations would be mutually consistent, and in agreement. We wouldn’t know that we were actually discussing the wrong colors.

The problem of course is that we’d be talking about two different things.

I’m hoping this will explain my bad taste in clothes.

Maybe we all have the same fovorite color, we just see it differently.

Is there any evidence to prove that all we all see colors the same way, i.e my red is your red, my blue is your blue, etc.

I see green. Do you see the same green?

And here I thought this was an original question. If a mod would like to close this, please do so. My apologies.

If they agree with Marx and Lenin, they’re red. Huh? Oh, never mind.