It's awful. Sorry. There are probably Jehovah's Witnesses that would have had my attention for longer. In fact it's so awful that it's inviting the reader to take delight into finding ways of feeling smugly superior to the author. It's just the kind of thing to make your non-rationalist friends want to un-friend you pretty quickly.

You don't even know which were the challenges you were supposed to rise up to in this article, otherwise you'd have at least paid lip service to them. You seem to come from a place of utterly failing to understand the cause of the usual blase attitude towards super-altruism - the part of typical human psychology which makes us generally not want to take the burden of the world upon our shoulders. You have to understand that in order to argue persuasively against it. Instead you just assume the contrary as a default. You also don't understand why hard things are hard, that is, hard as in, you don't just read an essay on the internet and decide that your aversion to doing a superhuman effort towards an unlikely goal is suddenly a thing of the past. And the writing itself flows as well as nails on a chalkboard. You can almost physically feel the pat on the head.

Your friends are not going to become optimizers or effective altruists. Especially not as a result of this essay. Get over it. It's a sign that their excessive-earnestness antibodies are working well, and that they have a well-calibrated sense of perspective with respect to their likely impact on the world. Sure, it wouldn't be good morals to try to talk you out of your itch to improve the world, as it might seem like I'm doing, but at the very least you could go about it in a less socially and psychologically oblivious way, because proselytizing for weird causes is textbook How To Lose Friends and Alienate People.

Which seems more unlikely: The sequences exactly matching, or the envelope sequence, converted to a number, being exactly 1649271 plus the flipped sequence converted to a number?

All sequences, both written and flipped, are equally improbable. The difference is in treating the cases where the two sequences are identical as logically distinct from all other possible combinations of sequences. They're not nearly as distinct as you might think; imagine if she's off by one. Still pretty improbable, just not -as- improbable. Off by three, a little less probably still. Equivalent using a Caeser Cipher using blocks of 8? Equivalent using a hashing algorithm? Equivalent using a different hashing algorithm?

Which is to say: There is always going to be a relationship that can be found between the predicted sequence and the flipped sequence. Two points make a line, after all.

Substantial? No - it adds up to normality. Interesting? Yes.

Imagine two situations of equal improbability:

In one, Alice flips a coin N times in front of a crowd, and achieves some specific sequence M.

In the other, Alice flips a coin N / 2 times in front of a crowd, and achieves some specific sequence Q; she then opens an envelope, and reveals a prediction of exactly the sequence that she just flipped.

These two end results are equally improbable (both end results encode N bits of information - to see this, imagine that the envelope contained a different sequence than she flipped), but we attach significance to one result (appropriately) and not the other. What's the difference between the two situations?

That's not the Chesterton's fence at all.

In plain words, the Chesterton's fence says that if you want to remove something because you don't understand why it's there, you should first find out why is it there.

That, as you notice, has nothing to do with "worked hard" or "took a long time".

How very deep. But if I'm not mistaken the original argument around Chesterton's fence is that somebody had gone through great efforts to put a fence somewhere, and presumably would not have wasted that time if it would be useless anyway. In your example, "the common practice of taking down Chesterton fences", this is not the case. The general principle is to not undo that which others have worked hard for to create, unless you are certain that it is useless/counterproductive. Nobody worked hard on making sure people could remove fences without understanding them (or at the very least I'm willing to claim that this is counterproductive), so this principle is not protected.

When someone removes a Chesterton fence without thinking about it much, what usually happens is that after a while people begin to see that there was a reason for the fence to be there. That doesn't necessarily mean that they have to put the fence back, but they do have to develop a new way to address the issues that were meant to be addressed by the fence. I expect this to happen over time with the fences that have been taken down in our current system (i.e. I think that those fences did have their reasons.)

I always maintain "If there is a quantitative difference, I sure as hell hope we never find it."

You may want to practice reciting the litany of Gendlin.

I think that'd lead to some pretty unfortunate stuff.

So have false beliefs about equality.

This does not addresses my question. The implication is "... shouldn't it follow that different races could have different brains—such that these differences are generalizable according to race?" [...] I think this implication was obvious.

In highly politically charged subjects it's very important to be explicit about your questions and not hiding your meaning in implications of your statements.

But apart from that it's not clear what the notion of generalizable differences that are not significant is supposed to mean. The standard way you would declare that a difference is generalizable is showing a stastically significant effect.

It's part of scientific reasoning to make claims that are in principle falsifiable. To do that you actually need to be precise over what you mean. There are contexts where it's okay not to practice high standards but if you want to discuss a topic like race differences that's politcally charged I think you have to practice high standards.

If you look at any two people they have different brains. Even if you look at the same person at different ages they have different brains.

If you care about the issue you have to make statements that are less vague.