Comment by sourcepluck

Very interesting, thanks for sharing.

I followed the two links from the comment on SE making the claim that Church's choice of lambda was completely arbitrary (pun intended). The first one doesn't seem to work, and the second one is a 2m youtube clip of Dana Scott talking about the subject.

I watched the video, the audio is a bit hard to make out in parts, and I'm left thinking the SE commenter interpreting Dana Scott, who you quote fully there, is overstating the case somewhat. Perhaps the claim should be moved from "likely true" to "somewhat uncertain", but not in any way "debunked" as the commenter says. Debunking means providing conclusive evidence against a claim, that any reasonable person would be obliged to agree with. Here we have an interesting and relevant anecdote, but it's still anecdotal, unfortunately.

Scott says a couple of things which are clearly audible that are relevant:

1. He asked John McCarthy personally why Church chose lambda, and McCarthy said he'd no idea,

2. Church never talked about the lambda calculus when he (Scott) was at Princeton, and

3. John Addison, Church's son-in-law, told Scott that he (Addison) wrote Church a postcard in which he asked him where he got lambda from, and that Church sent the whole postcard back to him with "eeny, meeny, miny, moe" written in the margins.

So I'm very happy you shared some more information on the subject, but I feel a conscientious biographer, for example, would be forced to include Scott's and Barendregt's theories and say that without confirmation from Church himself the matter is hard to decide. If anyone has a relevant quote from Church, I'd love to see it, but I presume it mustn't exist if Scott is so convinced there's no link.

I'm tempted to also point out more generally that all symbols are esoteric if you go back far enough, so I don't know if your particular quest could ever have been satisfied. In any case, I learned French beore Lisp, so I did have the experience of going, "oh, like in French? Why is that, I wonder?".