Only because we understand everything _except_ how it works.

how can we understand absolute everything and still don't know how it work ?

Trial and error :)

I wouldn't say that is "understanding". We must fully be able to explain to say that we understand it.

	▲	SirSavary an hour ago \| parent [-]
		There are two types of understanding: knowing how a candle works and knowing how a candle works.