McCarthy not only had an idea, he and his team a specific programming language. It even had a manual.

This is the Lisp I manual:

http://bitsavers.org/pdf/mit/rle_lisp/LISP_I_Programmers_Man...

He said Lisps and Lisp-2s, so obviously knows this.

I'm perfectly aware of that. My point stands - using a concrete language to generalize over some abstract ideas might be confusing for those who are unfamiliar. In general, Lisp dialects strive for simplicity.

That is exactly the reason why Scheme was chosen for SICP.

Can we agree on this?

“Lisp dialects strive for elegance.”

Elegance is not always synonymous with simplicity. For example, Smalltalk’s use of Class and Metaclass is very elegant, but most programmers encountering this for the first time would not call it “simple.”

After they got over the hump and grok how the two things work together to serve as the foundation for Smalltalk’s OOP and allow programmers to alter Smalltalk’s OOP... Then the elegance emerges.

I think elegance is a measure of the simplicity of a tool relative to the complexity of the problem domain, whereas simplicity feels like a more absolute measure.

Yes! This is probably the most accurate description. I take my hat off. Thank you!