Of course our physical computers know what to insert, since it was embedded in the binary. But it hasn't always been embedded "every time": there was a point in

Of course our physical computers know what to insert, since it was embedded in the binary. But it hasn't always been embedded "every time": there was a point in the past where someone's physical computer didn't know what to insert, and so they had to teach it by hand. Without the source code (or some human-entered code) at the end of the chain, we'd have to insist that the code was embedded from the very dawn of time, which would be rather absurd. Personally, I like how this article and other such projects push back on some of the mysticism around bootstrapping that sometimes floats around.