The difference is, the light switch switches on the light regardless if I believe in light switches. Thus it is comparable with conventional medicine rather than homeopathy.
And even though - just like with regular medicine - I don't have to know exactly how it works for it to function, I also don't have to have false beliefs how it works.
Do you think mainstream pharmaceuticals are 100% effective? They are analogous to a light switch that switches the light on/off about 60% of the time at best.
The placebo effect works 10-20% of the time. So we're talking about something that is almost as effective.
Most people taking advil OR those little homeopathic tablets know/understand nothing about how they work.
In the case of homeopathy, you don't need to know why it works -- in fact, knowing that it works via the placebo effect might undermine its effectiveness :)
And even though - just like with regular medicine - I don't have to know exactly how it works for it to function, I also don't have to have false beliefs how it works.