What was King Lear's diagnosis? There are two problems: firstly, he was a fictional character, and secondly, he is not available for tests or examination (a problem besetting all pathographers, though it also affords them infinite scope for pleasant speculation). So, screeds have been written in the last two centuries, but we are no nearer the truth—because there is no truth to come nearer to.

Let that not detain us. If we argued only about those matters that had a potentially definitive answer we should become boringly rational. Was Lear, then, demented, and if so was the …