"I fear oblivion. I fear it like the proverbial blind man fears the dark."
Oblivion. Let's ponder upon this word for one second. Oxford defines oblivion as "the state of being unaware or unconscious of what is happening around one".
For me its a tad bit different, but I'm not going into that right now - I'm going to take Augustus Waters' perception of it. Augustus Waters - Gus - is the lead from an enigma of a book "The Fault in Our Stars". He's seventeen years old, and had "a touch of osteosarcoma a year and a half back". How is he? He's grand. He's on a rollercoaster that only goes up, my friend. His words, not mine.
Coming back to the aforementioned phrase. Again, this is just my perception, and mine only. Augustus is afraid of being forgotten - afraid of the fact that no one will remember him. He does not know how that feels like yet - oblivion, that is. Much like a blind man who does not know what the dark is, but is afraid of it.
Who else but someone as awesome as John Green would put so much thought into one measly line? And who else but decidedly wonky and over-obsessive fangirls would put so much thought into squeezing the meaning out of said measly line? The book-reading(or enlightened) community is crazy indeed. Anyways, that was my take on the phrase.
I know, too much TFIOS, talk, right? To those who haven't read it yet,, I suggest that you immediately do. "Enigma" does not even begin to describe this book. And to those who have read it, they'll know what I'm rambling on about. :)