Rereading King Lear last night (no, I didn't feel moved, as Keats did, to write a sonnet), I started to think about the blinding of Gloucester. For me, this has always been the key to the tragedy. I saw a production of the play in 2002 at the Almeida. It was a play I had not read (going back to my childhood prejudice against Shakespeare: "Why doesn't he write happy endings?"), and, deliberately, I chose not to read it before the performance.
So the blinding of Gloucester was profoundly shocking to me. It remains a scene that I physically find difficult to read. Like the impulse to pull my arm away from a blood test, I pull my eyes away from the page.
Last night, I think I reached a more clear idea as to why this is at the centre of the play. It's not just the eye/sight imagery which builds from the very first scene or, as I decided and wrote two years ago for the Shakespeare paper, that sight is unmediated humanity and is thus opposed to the artificiality of speech, i.e. Lear needs to learn to trust his basic senses, to trust that he is loved and can love, rather than requiring proof through speech. The emotional truth (as represented in the play by sight) and speech's shifty potential reach a symbiosis in Edgar's closing words: Speak what we feel, not what we ought to say.
But now I've got another idea!!! And it relates to the 'comedy = tragedy + time' equation. The primary/immediate motive for Gloucester's blinding is his defiant line to Cornwall: 'but I shall see/ The winged vengeance overtake such children'. By blinding him, Cornwall symbolically denies this future to him. He stops time from being able to turn the tragedy of the present into a comic future since Gloucester will be unable to look back. Somehow, we need (or I need) the possibility of the future in order to make the tragedy bearable. Cornwall's actions make Lear unbearable not because Gloucester is denied future through death, but because he has to go on living, to enter a bleak future in which his scarred and bloody eyes deny him (and us) hope.