> Which one was the first spend and which one was the double-spend? The answer to that question is actually that it doesn't matter. Seems weird at first but if

> Which one was the first spend and which one was the double-spend? The answer to that question is actually that it doesn't matter. Seems weird at first but if you think about it, no one who uses the system cares which one is "the first" the only thing people care about is that once one is picked it will not change later on aka finality. And for that a majority must agree on one. Which one again doesn't matter at all. FBA (Federated Byzantine Agreement) "blockchains" make use of that. Each node signals which Tx it saw first but if no super-majority can be reached it simply switches to the Tx that has more votes. The sole purpose is to agree on one which makes the second Tx unfunded and thus fail. Bitcoin and bitcoin-like system cant do this. They always have some kind of lottery that decides who writes the Tx. There is no agreement and thus no finality and that's the whole reason why double-spends can happen.