Are there 2 ways to wire a ceiling light?
Assuming you are speaking of the neutral (grounded) conductor, until relatively recently it was not common for it to be routed through a switch box.

Switches (and timed switches) control associated loads by connecting/disconnecting the hot wire, so running the neutral wire through a switch box was unnecessary. Modern switches including digital timers often require a neutral, making it difficult to use those in older buildings.