Sometimes he thinks, perhaps, that he is a dream of Alice's.
A dream cannot be dreamed unless the dreamer is asleep, provided that one cannot dream while awake, in which case, it would be more delusion than dream. So if he were a dream of Alice's, then would he not simply wink out upon her waking? Only to wait, and live again while Alice dreamed? He has memories that seem older than Alice. They dance behind his eyes, but if one dreams of a man who has memories, then memories he shall have – whether or not such remembrances are actual and factual. So it seems quite possible that he is a dream of Alice's, and that all the while he is living, she is dreaming, even if she isn't part of the dream herself.
In a way, he likes this thought. He likes that he might be her dream, because if he is in Alice's mind then she cannot forget him, and if she ever did forget him, then he would cease to exist and it wouldn't much matter anymore. But he also doesn't like this idea, although the reason for that dislike is much harder to place. But at least he is certain that if he must be someone's dream, he could not pick a madder dreamer than Alice, and that is a very approvable state of affairs. He probably wouldn't like being someone else's dream. Having some stranger watch him, what an unsettling thought! Who knows what dark and gruesome things might prod at their minds? They could change his life with the blink of an eye, and he would find himself a sensible gentleman with no taste for tea and some small black bowler atop his head.
A banker, even.
No, no no no, that would not do. He would rather Alice forget him than that he should find himself as the dream of someone sensible. Of course, it would be unlikely that he should be dreamed up by someone sensible to begin with, as a dream of his life would be sure to drive someone mad, and only someone who was already driven mad would be able to dream of his life. So that is the end and the start of it, really. If he is a dream then he is Alice's dream, and if he is not a dream…
If he is not a dream… then perhaps Alice shall forget him, and he shall always carry on as he has, and never know that he is no longer meant to exist. Because he is not a dream, so he will continue on even without Alice. But if Alice does not come back, then who is the empty chair for? He has already poured her tea, although he supposes it will be some time yet before she drinks it. If she ever does.
And if she never does, then, well, perhaps the tea is for a dream of his own.