There’s (at least one) voice in your head and it’s there for a reason. When we were scrambling around in the dirt trying to work out which way was up, it was that voice that spoke to us. It’s a dangerous voice, a voice that is brash instead of wise, totally and completely unconcerned with repercussions. It wants to see what happens when the raw meat gets thrust into the fire, that asks why we can’t fly or what happens when we die. It’s that what-happens-when voice I think we need to harness.
And that way lies madness, too. I’m sure there have been a lot of people in the world who’ve done the things they’ve done purely to see what would happen if they did.
Listening to that voice, even if you only do it a little, is where your ideas are going to come from. Everything new and crazy and, yes, even dangerous, comes from that voice. And good fiction is all of those things and more.