Theism. Couldn't keep it. In the end, it wasn't so much that the evidence was good -- it had always been good -- as that I lost the conviction that "holding out" or "staying strong" against atheism was a virtue.

Standard liberal politics, of the sort that involved designing a utopia and giving it to people who didn't want it. I had to learn, by hearing stories, some of them terrible, that you have no choice but to respect and listen to other people, if you want to avoid hurting them in ways you really don't want to hurt them.

Question: Which strongly held opinion did you change in a notable way, since learning more about rationality/thinking/biases?

There seems to be an important point here, but it all seems a little un-rigorous, rather like you just did a post on methods of alchemy or astrology.

In the end, it turned out that the alchemists were on to something (chemistry and nuclear physics) but the astrologers weren't. At this level of speculativeness, how can we tell which kind of pre-science this is? Is there good any peer-reviewed research on the predictive value of these ideas?

I voted for the karma-coward option because people are different, so having more options is good. But being new myself (only 16 comments, 43 karma points), you might be more interested in the fact that I would not use them if they were available.

I find it very gratifying to receive karma points. It motivates me to write more comments. If I was granted a grace period in which my comments did not receive karma points, I might have posted even less. Even the downvotes are a motivator, not to post more, but to put more effort next time I have something to say.

When I post a comment, a part of me does it to earn more karma points. If I expect that a comment will get downvoted, I rephrase it until I expect it to be accepted by the community. Therefore, even if I was the kind of person who needs protection from those scary downvotes, I would never cover my comments with cowardliness, as I would never expect the downvotes in the first place.

Sure, let's try.

okay, writing down my thoughts. seems easy enough. reminds me of this exercise where we needed to write down our thoughts without thinking about it and i was mad because I kept thinking private thoughts and writing "can't write this" but in a very pleasing way and i liked being liked and that's a pattern which characterizes me well and i stopped- why? to catch my breath. not to think about the next sentence? are you sure? I put a lot of importance on writing down clearly and smartly I want readers to feel how smart I am, I want to be appreciated, I need to be appreciated, I am appreciated but still not enough yet. private thoughts again. girls. I hate how "boy thinks private thoughts about girls" tends to be interpreted as sex thoughts by default.

Wow. "This person" seems to care a hell of a lot more about the opinion of others than I thought I did. Among my friends, I am known as the clown, the person who will readily wear the hat of ridicule if the situation arises. It seems like this might be a front after all. I need to find a way to confirm this.

I will definitely perform this exercise again in the future. It was easy to perform, and the results surprised me, so in terms of information, I had a very high return on investment. Thanks, Alicorn!

There is no particular reason to assume that if the stars are moving away from each other right now, then they must always have done so. They could be expanding and contracting in a sort of sine wave, or something more complicated.

The key is there at the end of your quote. From the first set of observations (of relatively close galaxies), the simplest behavior that explained the observations was that everything was flying apart fast enough to overcome gravity. This predicted that when they had the technology to look at more distant galaxies, these too should be flying away from us, and at certain rates depending on their distance.

When we actually could observe those more distant galaxies, we did in fact see them red-shifted as predicted. This alone should be enough to put the "sine wave" theory in the epistemic category of "because the Dark Lords of the Matrix like red shifts", because the light left these galaxies at all different times! It would take a vast conspiracy for them all to line up as red-shifted right now, from our perspective.

With strong evidence in hand that the galaxies had been flying apart for billions and billions of years, the scientists then noticed an irregularity: the velocities of those distant galaxies were different from the extrapolation made on the early data! However, they differed in a patterned way, and the simplest way to account for this discrepancy was a variant of Einstein's "cosmological constant" idea.

Additional support for the Big Bang:

• Stephen Hawking calculated that there would have been no way for matter to fly towards a point, "miss" colliding with itself, and fly apart in an apparent expansion without a singularity and Big Bang. (This is somewhere in A Brief History of Time, but Google Books won't let me find it.)

• We can roughly estimate our galaxy's age by other means (i.e. how much hydrogen has been used up in stars, how much is left). Have you looked into this, to see whether the estimates thus derived are consistent with the estimate of about 10 billion years that the Big Bang theory implies?

• Finally, the cosmic background radiation gives us way more than one bit of data; its spectrum is precisely the black-body radiation one expects from a Big Bang.

ETA: Also, this seems like exactly the sort of issue where the "physicist-test" applies, as described above. For example, being critical of QM on common-sense grounds (of course the electron has to go through one slit or the other!) doesn't make for discriminating skepticism, since one should assign high probability to physicists having strong evidence to this effect if they're claiming something weird, or else one should have strong evidence that common sense usually beats the consensus of the physics community. Needless to say, I wouldn't hold my breath on the second claim.

but now I can bump my estimate back up. There is at least one belief which my tribe elevates to the rank of scientific fact, yet which I think is probably wrong: I do not believe in the Big Bang.

I don't think we can reasonably elevate our estimate of our own rationality by observing that we disagree with the consensus of a respected community.

Second, the background radiation which is said to be leftover stray photons from the big bang. If the background radiation was a prediction of Big Bang theory, then I might have been convinced by this experimental evidence, but in fact the background radiation was discovered by accident. Only afterwards did the proponents of Big Bang theory retrofit it as a prediction of their model.

I am wary of this kind of argument. I should not be able to discredit a theory by the act of collecting all possible evidence and publishing before they have a chance to think things through.

If the background radiation was a prediction of Big Bang theory, then I might have been convinced by this experimental evidence, but in fact the background radiation was discovered by accident. Only afterwards did the proponents of Big Bang theory retrofit it as a prediction of their model.

Not true; Alpher & Gamow predicted the radiation, although they were off by a few kelvins.

there is no particular reason to assume that if the stars are moving away from each other right now, then they must always have done so. They could be expanding and contracting in a sort of sine wave, or something more complicated.

True, but this lacks parsimony, & the mechanism by which the "sine wave" (or whatever) could be produced is unknown. The universe is expanding now, implying some force behind the expansion. Gravity is attractive only. Celestial objects almost all have net electric charge as close to 0 as makes no odds, so they do not repel each other. The strong nuclear force is always attractive too. You see what I mean? What could possibly cause the outward oscillation, if not extreme density? It's not like when stars come close to each other they suddenly feel a repulsion.

I don't see how you can make sense of this without the Big Bang, except by positing unknown physical forces or something.

Very interesting post though. You seem curious; I'd recommend Jonathan Allday's book "Quarks, Leptons & the Big Bang" on this subject. It's reasonably technical, given that it's not a textbook.

I've been following Alicorn's sequence on luminousness, that is, on getting to know ourselves better. I had lowered my estimate of my own rationality when she mentioned that we tend to think too highly of ourselves, but now I can bump my estimate back up. There is at least one belief which my tribe elevates to the rank of scientific fact, yet which I think is probably wrong: I do not believe in the Big Bang.

Of course, I don't believe the universe was created a few thousand years ago either. I don't have any plausible alternative hypothesis, I just think that the arguments I have read in the many popular science physics book I have read are inconclusive.

First, these books usually justify the Big Bang theory as follows. Right now, it is an observable fact that stars are currently moving away from each other. Therefore, there was a time in the past where they were much closer. Therefore, there was a time where all the stars in the universe occupied the same point. It is this last "therefore" which I don't buy: there is no particular reason to assume that if the stars are moving away from each other right now, then they must always have done so. They could be expanding and contracting in a sort of sine wave, or something more complicated.

Second, the background radiation which is said to be leftover stray photons from the big bang. If the background radiation was a prediction of Big Bang theory, then I might have been convinced by this experimental evidence, but in fact the background radiation was discovered by accident. Only afterwards did the proponents of Big Bang theory retrofit it as a prediction of their model.

Third, the acceleration. The discovery that the expansion was accelerating was a surprise to the scientific community. In particular, it was not predicted by Big Bang theory, even though it seems like the kind of thing which an explanatory model of the expansion of the universe should have predicted right away.

Fourth, the inflation phase. This part was added later on, once it had been observed that Big Bang theory did not fit with the observed homogeneousness of the cosmos. To me, this seems like a desperate and ad hod attempt to fix a broken theory.

Now, it could be that all these changes are a progression of refinements, just like Newtonian physics was adjusted to take into account the effects of relativity, and just like the spherical Earth was adjusted to make it an elliptical Earth. But the adjustments which Big Bang theory has suffered seem like they should change the predictions completely, rather than, as in the other cases, increasing the precision of the existing theory.

I am, of course, open to being convinced otherwise. If Big Bang theory really is true, then I wish to believe it is true.

I'm rather happy with my Zs and omegas, but some of my dear ones aren't.

I expect that this sequence will allow me to give them more educated suggestions about how to fix themselves up, but based on past experience, they will most likely nod in agreement, yet go on using the dysfunctional coping method they've been using for years. This expected lack of result will, of course, not prevent me from eagerly awaiting the next instalment of your sequence.