Opposition and/or Origin

Some concepts are said to derive their meaning from their opposite. For instance, light supposedly requires the dark for us to make sense of the concept.
I think we would never have arrived at the concept of light, even when it was exchanged now and then by darkness, if we had never seen whence light originates: lamps, or the sun.

Else, what darkness would make us conceive of is objects—which are invisible in the dark, visible in light. Light is invisible itself, its origin isn’t. (Thanks to Anna, for getting me to realise this.)