For high-frequency (or mid-frequency) trading, 1% of the transaction is 3 or 4 times the expected value from the trade.

I'm very much not sure discouraging HFT is a bad thing.

this probably doesn't matter unless the transaction tax REPLACES other taxes rather than being in addition to

I imagine that it would replace/reduce some of the other taxes so the government would get the same amount of money.

it encourages companies to do things in-house rather than outsourcing or partnering, since inside-company "transactions" aren't real money and aren't taxed

But normal taxes have the same effect, don't they?

I came up with the decision theory problem. It has the same moral as xor-blackmail, but I think it's much easier to understand:

Omega has chosen you for an experiment:

1. First, Omega predicts your choice in a potential future offer.
2. Omega rolls a die. Omega doesn't show you the result.
3. If Omega predicted you would choose $200, they will only make you an offer if the die shows 6.
4. If Omega predicted you would choose $100, they will make you an offer if the die shows any number except 1.
5. Omega's offer, if made, is simple: "Would you like $100 or $200?"

You received an offer from Omega. Which amount do you choose?

I didn't come up with a сatchy name, though.

First (possibly dumb) thought: could it be compensated by printing fewer large bills? Again, poor people would not care, but big business transactions with cash would become less convenient.

Wow, really? I guess it's American thing. I think I know only one person with the credit card. And she only uses it up to the interest-free limit to "farm" her reputation with the bank in case she really needs a loan, so she doesn't actually pay the fee.

Epistemic state: thoughts off the top of my head, not the economist at all, talked with Claude about it

Why is there almost nowhere a small (something like 1%) universal tax on digital money transfers? It looks like a good idea to me:

• it's very predictable
• no one except banks has to do any paperwork
• it's kinda progressive, if you are poor you can use cash

I see probable negative effects... but doesn't VAT and individial income tax just already have the same effects, so if this tax replace [parts of] those nothing will change much?

Also, as I understand, it would discourage high-frequency trading. I'm not sure if this would be a feature or a bug, but my current very superficial understanding leans towards the former.

Why is it a bad idea? 

I guess the big problem for someone who tries to do it not in small form is that while you write the story it is already getting old. There are writers who can write a novel in a season, but not many. At least if we talk about good writers. Hm-m-m, did rationalists try to hire Stephen King? :)

I often think something like "It's a shame there's so little modern science fiction that takes AI developments into account". Thanks for doing something in this niche, even if in such small form!

I always understood it as "not pull -> trolley does not turn; pull -> trolley turns". It definitely works like this on the original picture.