I can't remember where it is (somewhere in the middle), but I like the part where Alan Kay describes (paraphrasing) programming languages as 'Idealized machines

I can't remember where it is (somewhere in the middle), but I like the part where Alan Kay describes (paraphrasing) programming languages as 'Idealized machines', and that if we layer ideal machines on top of each other it increases the pleasure of programming at the cost of performance.