Why is the symbol of an idea a light bulb coming on?

Au contraire, Jo'e (french for Joey).

Light bulbs are among the greatest minds to walk this Earth. I mean, there's Iridesca Watts of Sweden, Fluorescent Spark of Jamaica, etc.

I've heard, that if you look really hard at the Mona Lisa, you can see Einstein in his true form: A light bulb with bishy hair and glasses!! Oui, tis true!

Because when brilliant people like Napoleon or Socrates had an idea, they would hold a light bulb over their head.

After that, the whole thing just stuck to this day.

Light became a symbol of knowledge because of it's illuminating quality. Lighting up someplace dark is an analogy of harnessing an idea during a time of confusion.

Have no clue. But it makes the BEST line in any song, ever made:

"It's clear from your vacant expression, the lights are not all on upstairs".

Be Prepared from 'The Lion King'.

I don' t know. Maybe a lightbulb fell on top of Thomas Eddison's head.

It was an idea got by Thomas Elva Edison who invented bulb and given light to the whole wide world. So they show the idea with the bulb.

Because that is what it feels like. Everything is dark and you can not see the answer then suddenly a light comes on and all is clear.

Because ideas are usually brilliant, like a light bulb.

Cartoonists wanted to express on how a cartoon character came up with an idea.

because a good idea lights up the darkness of uncertainty and sheds light on the path that should be taken.

"bright idea"

the symbolization of the light bulb came from the term bright idea

and of course, light bulbs are bright ^^;;;