When I was a child, I thought like a child. While appropriate for his time, this is an example of childish thinking on the part of CSP.
Is there any knowledge à priori? All our thought begins with experience, the mind furnishes no material for thought whatever. This is acknowledged by all the philosophers with whom we need concern ourselves at all. The mind only works over the materials furnished by sense; no dream is so strange but that all its elementary parts are reminiscences of appearance, the collocation of these alone are we capable of originating.
Here is an example of grownup thinking from GSB: "There can be no distinction without motive, and there can
be no motive unless contents are seen to differ in value." While I have yet to commit the entire in injunctive recipe to paper, it is non-the-less true that computing entities of all forms follow directly from Laws of Form. The simplest computing machine is the Turing Machine which consists of a finite-state-machine and the tape(s) upon which it operates. Every computing entity starts with some a priori knowledge. The knowledge is contained in its FSM and the initial contents of its tape(s). That we are many levels of abstraction and complexity away from a Turing Machine does not cancel the fact that a Creator with His own "motive" created us. He obviously made our computing self-aware because we are, and nothing can happen by "accident". We no longer have to discuss what "all the philosophers with whom we need concern ourselves" think. The task of reading the "script(ure)" is sufficient to occupy our time.
In the notes to Chapter 2, GSB notes this: 'We cannot fully understand the beginning of anything until we see the end." Lucky for us, the CotU who "determined the end from the beginning", has written down the whole script(ure) for us to read.