>>24659008
>the proofs are taught "synthetically," i.e., in an organized manner so that what comes successively is shown in relation to what's come prior. The text doesn't say anywhere, "By the way, later props are deduced from earlier ones," that's an assumption readers smuggle in or are mistakenly taught.
Picrel is from: https://archive.org/details/euclid_heath_2nd_ed/1_euclid_heath_2nd_ed
See my highlight. It says there:
>[I.1]
That's referencing proposition 1 which came just before this proposition. Did Euclid put it there or did Heath? Do you think it's not deductive logic in how proposition 1 is required to construct that part of proposition 2? If so, why?

Almost all the resources and materials I've seen which present Elements have these references, in the text, in a column, the margin or spoken. They reference not only definitions, common notions and postulates, but also previous propositions. See:

https://youtu.be/UHZO2dviZfU

http://aleph0.clarku.edu/~djoyce/java/elements/bookI/propI2.html