I think that in general people's ethical opinions are substantial, though certainly not conclusive, evidence for the truth of those opinions.
I disagree with that, but arguing it in the general case would take us on a long-winded tangent. As long as we agree that the majority ethical opinion is found to be wrong rather frequently (with sufficient frequency to suspect that we might have discovered another flaw recently), the exact degree to which different kinds of evidence are reliable are irrelevant.
None of this seems to have anything to do with Lob's theorem, which is about formal proofs and self reference within logical systems.
The relevant explanation is in the post that the word 'before' links to. Basically, if you consider your own belief as evidence for something, you can believe anything and have evidence for it. (The evidence being your own belief in it.)
Does PB make it less likely that CR law to exist in the future?
Is that what you mean by 'undermine'? It may or may not affect the probability of CR laws existing in the future, but what it does is enable large-scale violations of CR law and thus make it very difficult to enforce. That is what I mean by 'undermine'.
I would maintain this in the face of (3) if filesharing in infringement of CR law was done with the aim of self-interest and if it had no plausible connection to making CR laws less likely in the future.
I really don't get what you're getting at here. Violations of the law are only moral if they help in the repeal of the law, but not in and of themselves? But... why say the law is immoral, unless it prevents moral acts or rewards immoral acts?
Ah, I guess the answer to that is in the question itself. A law can be immoral, yet some parts of it can be perfectly moral.
So let me add to my original conditions: (2.5) That if free sharing of copyrighted materials were moral, copyright law would be immoral?
And (4.5) Even if free sharing of copyrighted materials were moral, downloading something off the Pirate Bay would still be immoral, as it must, by your definition of 'personal gain', lead to personal gain for the downloader?
Basically, if you consider your own belief as evidence for something, you can believe anything and have evidence for it. (The evidence being your own belief in it.)
I think it's pretty reasonable to consider my belief for something as evidence for it, but I agree that this can't be the end of the story. For instance, I consider my belief that my car is green as evidence for the greenness of my car, but because I also have reason to believe that I'm familiar with the color of my car, I have reliable eyesight, there's no reason that it might have been repa...
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.