Most neuroscientists locate consciousness in our wrinkly cortexes, the outer layer of our brains where thought and sensation are supposed to live. But a growing band of rebels says the lights of experience may switch on far deeper, in the brain’s ancient core. And that cracks the door open to an even stranger idea. Could awareness be everywhere?

Philosopher Ned Block and physicist Sean Carroll debate whether AI can ever be conscious or if minds require meat-based biology.