If you know German, Schönfinkel’s 1924 paper is a fascinating read.
Nice tip, thanks.
I googled it and it is available in English by the name “on the building blocks of mathematical logic”. Quite an interesting read indeed.
I love when I can get a historic perspective on mathematics.
I bumped into Phil Wadler in a talk and asked him where did type theory come from. He was genuinely interested when I asked if it came from Russell. And that’s Wadler - he’s forgotten more about type theory than I can ever hope to learn.