I realise that there were a lot of unnoticed background assumptions in my original post.
(3) Consider whether I actually want a copy enough to bother paying for it; if so, buy it.
Here is where my assumptions trip up; my reaction to a 'not sure' at this stage would be 'whatever, let's just download it and see if it's interesting/useful'. While your reaction seems to be 'borrow it from library', or, failing that, 'meh, screw it'.
I am not claiming that this policy is optimal for me
Come on, that's just equivalent to throwing in the towel. Why not look for ways to optimise it if it's not optimal?
I have a backlog of something like 350 books sitting on my shelves waiting to be read.
How many of those do you think you'll ever actually read? I see that as a phenomenal waste of money.
by introspection, having more money as a result of pirating books rather than buying them would not make me give more to charitable causes
I maintain that this is sub-optimal, and that which is sub-optimal should be optimised. I find it inconceivable that you can't find any good use for the money you save by not buying books... So why wouldn't you put it to those uses?
I very much prefer having physical copies of the books I read
This is one of the things that I really can't argue against without arguing that people shouldn't have exclusive rights to decide where they spend their money. I'm not willing to bite that bullet just yet.
I can point out that this preference might just be status quo bias. Of course, that's not necessarily the case.
I do have one (1) Fully General Counterargument though, read on....
it pleases me that the people whose books I enjoy reading get some benefit from my reading them
Ah, but does that really rank higher on your preference rankings than existential risk reduction?
But this does show me that my view was overly simplistic and that I've veered too far into other-optimisation. I should probably end this discussion now.
Why not look for ways to optimise it if it's not optimal?
Because there are a million other things in my life that aren't optimal, and the way I deal with books leaves me reasonably well satisfied even though it may not be optimal. (Note also that I only said I don't claim it's optimal even for me; it may in fact be optimal for me, but I don't have any sort of proof and don't wish to spend the time and energy it would take to defend the claim if I made it.)
How many of those do you think you'll ever actually read?
Approximately all of them. My book-rea...
See also: Twelve Virtues of Rationality, The Meditation on Curiosity, Use Curiosity
What would it look like if someone was truly curious — if they actually wanted true beliefs? Not someone who wanted to feel like they sought the truth, or to feel their beliefs were justified. Not someone who wanted to signal a desire for true beliefs. No: someone who really wanted true beliefs. What would that look like?
A truly curious person would seek to understand the world as broadly and deeply as possible. They would study the humanities but especially math and the sciences. They would study logic, probability theory, argument, scientific method, and other core tools of truth-seeking. They would inquire into epistemology, the study of knowing. They would study artificial intelligence to learn the algorithms, the math, the laws of how an ideal agent would acquire true beliefs. They would study modern psychology and neuroscience to learn how their brain acquires beliefs, and how those processes depart from ideal truth-seeking processes. And they would study how to minimize their thinking errors.
They would practice truth-seeking skills as a musician practices playing her instrument. They would practice "debiasing" techniques for reducing common thinking errors. They would seek out contexts known to make truth-seeking more successful. They would ask others to help them on their journey. They would ask to be held accountable.
They would cultivate that burning itch to know. They would admit their ignorance but seek to destroy it.
They would be precise, not vague. They would be clear, not obscurantist.
They would not flinch away from experiences that might destroy their beliefs. They would train their emotions to fit the facts.
They would update their beliefs quickly. They would resist the human impulse to rationalize.
But even all this could merely be a signaling game to increase their status in a group that rewards the appearance of curiosity. Thus, the final test for genuine curiosity is behavioral change. You would find a genuinely curious person studying and learning. You would find them practicing the skills of truth-seeking. You wouldn't merely find them saying, "Okay, I'm updating my belief about that" — you would also find them making decisions consistent with their new belief and inconsistent with their former belief.
Every week I talk to people who say they are trying to figure out the truth about something. When I ask them a few questions about it, I often learn that they know almost nothing of logic, probability theory, argument, scientific method, epistemology, artificial intelligence, human cognitive science, or debiasing techniques. They do not regularly practice the skills of truth-seeking. They don't seem to say "oops" very often, and they change their behavior even less often. I conclude that they probably want to feel they are truth-seeking, or they want to signal a desire for truth-seeking, or they might even self-deceivingly "believe" that they place a high value on knowing the truth. But their actions show that they aren't trying very hard to have true beliefs.
Dare I say it? Few people look like they really want true beliefs.