> The "abstractions" we manipulate are not, in point of fact, abstract. They are backed by real pieces of code, running on real machines, consuming real energy,

> The "abstractions" we manipulate are not, in point of fact, abstract. They are backed by real pieces of code, running on real machines, consuming real energy, and taking up real space. [...] What is possible is to temporarily set aside concern for some (or even all) of the laws of physics. – Gregor Kiczales, 1992