Let’s see. You could survive in a darkened cell for quite a long time, couldn’t you, as long as you had warmth, food and water.
But in that case how much of you would be alive? Your body would be ticking over, but what would your brain be doing?
What if the imprisoned-in-the-dark person was an artist? Would he be more alive than someone without such a developed imagination?
Might an artist be more alive in the darkened room than out in the world?
Or just a bit madder?