Here are two old handwritten papers by Robin Milner that @jer_gib helped me track down, and a few thoughts on them. https://decomposition.al/blog/2025/11/20/where-simulation-came-from/
Where “simulation” came from

decomposition ∘ al
@lindsey @jer_gib I never met Robin Milner, which makes me sad. His writing is so lucid, and suggests so much care in his thinking. He goes in the list of folks for whom I wish I had the time to read all their papers.

@rg9119 @jer_gib Yeah. I might just be a hopeless romantic, but especially with these handwritten papers, the care put into each word is evident.

My student Nathan pointed out how the phrase "we show how the real program simulates (in a precise sense) the ideal program that never got written" makes it stunningly clear which way simulation goes. I have always had to think, "wait, which thing simulates which, again?", but after reading that one phrase, I feel like I will never again forget.