 My theory on Caan is that being sucked through the Time War and blown out the other end has kind of reverse @-@ wired — or random @-@ wired — his brain , so all his neurons are firing in constantly changing , random , insane ways . That 's why he doesn 't really know what 's funny or serious . He just knows the truth , and it blurts out in this odd , cryptic way . I think he 's frozen in a moment of excrutiating ecstasy . When any emotion surges up inside him , it makes him laugh , whether its appropriate or not . 
