A cucumber is bitter--throw it away. There are briars in the path--turn aside from them. This is enough. Do not add, "And why were such things put into the world?"

--Marcus Aurelius, Meditations, 8.50

Which is exactly Dennett's point in context: the idea that you are a brain in a vat is only conceivable if you don't think about the computing power that would be necessary for a convincing simulation.

Dreams can be quite convincing simulations that don't need that much computing power.

The worlds that people who do astral traveling perceive can be quite complex. Complex enough to convince people who engage in that practice that they really are on an astral plane. Does that mean that the people are really on an astral plane and aren't just imagining it?

It just takes some imagination. Hollow out both the Earth and the Moon to reduce their gravitational pull; support the ladder with carbon nanotube filaments; stave off collapse by pushing it around with high-efficiency ion impulse engines; etc.

I agree, though, that philosophers often make too much of the distinction between "logically impossible" and "physically impossible." There's probably no in principle possible way to hollow out the Earth significantly while retaining its structure; etc.

That's an interesting opening comment on regretting choosing to speak more than choosing not to speak. In particular, it brings to mind studies of the elderly's regrets in life and how most of those are not-having-done's versus having-done's. These two aren't incompatible: if we remain silent 20 times for every time we speak, then we still regret remaining silent more than we regret speaking even if we regret each having-spoken 10 times as much as a not-having-spoken. Still, though, there seems to be some disagreement.

It is said, for example, that a man ten times regrets having spoken, for the once he regrets his silence. And why? Because the fact of having spoken is an external fact, which may involve one in annoyances, since it is an actuality. But the fact of having kept silent! Yet this is the most dangerous thing of all. For by keeping silent one is relegated solely to oneself, no actuality comes to a man's aid by punishing him, by bringing down upon him the consequences of his speech. No, in this respect, to be silent is the easy way. But he who knows what the dreadful is, must for this very reason be most fearful of every fault, of every sin, which takes an inward direction and leaves no outward trace. So it is too that in the eyes of the world it is dangerous to venture. And why? Because one may lose. But not to venture is shrewd. And yet, by not venturing, it is so dreadfully easy to lose that which it would be difficult to lose in even the most venturesome venture, and in any case never so easily, so completely as if it were nothing...one's self. For if I have ventured amiss--very well, then life helps me by its punishment. But if I have not ventured at all--who then helps me?

--Soren Kierkegaard, The Sickness Unto Death

I'm someone who still finds subjective experience mysterious, and I'd like to fix that. Does that book provide a good, gut-level, question-dissolving explanation?

He [the Inner Game player] reasons that since by definition the commonplace is what is experienced most often, the talent to be able to appreciate it is extremely valuable.

--W. Timothy Gallwey, Inner Tennis: Playing the Game

From the remarkable opening chapter of Consciousness Explained:

One should be leery of these possibilities in principle. It is also possible in principle to build a stainless-steel ladder to the moon, and to write out, in alphabetical order, all intelligible English conversations consisting of less than a thousand words. But neither of these are remotely possible in fact and sometimes an impossibility in fact is theoretically more interesting than a possibility in principle, as we shall see.

--Daniel Dennett

The chief trick to making good mistakes is not to hide them — especially not from yourself. Instead of turning away in denial when you make a mistake, you should become a connoisseur of your own mistakes, turning them over in your mind...

Daniel Dennett

To recognize that some of the things our culture believes are not true imposes on us the duty of finding out which are true and which are not.

--Allan Bloom, Giants and Dwarfs, "Western Civ"