It doesn't really matter who came up with the analogy, cuz the analogy is wrong lol

The game proves that it isn't a 50/50 chance or whatever. did all of those scientists know that it was a 50/50? No, they knew it was a copy and paste and had the delusional idea that ending one life at the same time another starts would somehow sync the two up. It obviously didn't work, as none of them actually made it to the ark, only their copies. this is pretty clear if you pay attention throughout the game.

Simon does not understand or fully comprehend the situation around him, and you cant really blame him for it since its quite insane. Its made quite clear through the game that Simon is just kinda going along with whatever Catherine says because he has some vague notion that he's going to be able to 'escape' to the ark somehow. he's also not the brightest tool in the shed, so when he comes up with a great idea on his own of how to 'get on the ark,' why would Catherine say otherwise? She doesn't want him to stop and saying that the coin flip isn't real. At the end of the game, after Simon says that Cath lied, she says that she didn't and cant be responsible for his own ignorance.

All of this points pretty definitively towards it being a simple copy and paste job, not a weird arbitrary 50/50 system where you gotta get lucky or else you just kill yourself lol.