We interrupt this debate to bring you a halachic point…
Some have claimed that most bulbs today are not incandescent, which is considered aish and a d’Oraisa according to all accepted opinions, but rather fluorescent, so we would be dealing with a d’rabbonon.
This might be true of LED (if electricity itself is not d’Oraisa, which is a big machlokes), but fluorescent bulbs do in fact have glowing filaments on either end, and are considered aish.