Philosophers do it a posteriori . Philosophers do it conceptually. Philosophers do it for pure reasons. Philosophers do it with their minds. Philosophers think about doing it.
Philosophers wonder why they did it.
One to change it and two to stand around arguing over whether or not the light bulb exists. Two, of course. This dialectic creates a synthesis which does the job. One to change it, and one not to change it. One to change the lightbulb and one to observe how the lightbulb symbolizes an incandescent beacon of subjectivity in a netherworld of Cosmic Nothingness.