This excerpt is from Vincent’s Cheung’s Presuppositional Confrontations.
“Imagine that we are watching a game of tennis on television, although for our purpose it can be just about any kind of game – basketball, football, or even chess.”
A Priori Knowledge vs. Blank Slate Sensory Experience
“Suppose that I know the rules of tennis, but you do not. And suppose further that we have muted the television, so that we receive no verbal communication from the commentator. Finally, suppose that there is no visual communication, so that not even the scores are shown. Now, my question is whether the game will be intelligible to you at all.”
A Priori Knowledge
If I pay close attention, I should still be able to follow the game even without any verbal communication, because I already know the rules of the game. Likewise, the players themselves should be able to follow the game without constant assistance from the announcer or the scoreboard.
Blank Slate Sensory Experience
On the other hand, although you are watching the same game, you will not be able to make sense out of what you are seeing, since you do not know the rules. This means that when you are watching a game, what you observe does not provide its own intelligibility and interpretation.
The Necessity of A Priori Knowledge
Rather, for a game to be intelligible to you and for you to have the correct interpretation of what is happening, you must bring a considerable amount of knowledge to the act of watching the game, and this knowledge does not come from watching the game itself.
If I had explained the rules before the game, or if I explain the rules as we are watching the game, then what you are watching will become intelligible, and you will be able to correctly interpret what you are seeing.
Can Observation Produce Knowledge?
You may argue that it is possible to derive some of the rules by observation. But this is not as simple as most people think.
For example, suppose you observe that after every “checkmate,” the two players would walk away from the chessboard. What can you infer from this? You cannot infer that one of them won unless you know the rules. Perhaps “checkmate” means a draw. Perhaps it means that the players are bored and decide to give up chess. Maybe it means that it is time for lunch.
You need to know that it is a game, that it can be won or lost, and how it is won or lost. Even if you infer that one of them won, where did you obtain the categories of “winning” and “losing” in your thinking? You cannot get them from observing the game itself. You must bring these ideas to the act of observation.
What about the ideas of time and causation? They are required to make sense of a game, but you cannot derive them from watching the game. You must bring these ideas to the act of observation.
Some ethical principles are also presupposed. You must assume that the players would not usually cheat, and that the players cannot get away with cheating, or else the game would not have sufficient regularity for you to derive any rules from it. However, if a person cheats and gets away with it, how will you know that he is cheating, or if his action is just an exception allowed by the rules?
If we take the time to enumerate, we can make explicit dozens, or more probably hundreds or even thousands of presuppositions that are necessary for the game to be intelligible to your observation, when at the same time these presuppositions cannot come from the act of observation.
To make matters more difficult, there are thousands of arbitrary elements to every game that are not essential to the rules, although they are objects of observation. For example, if a chess game is played by two men in formal attire, what can you infer from this? Are you to infer that this is an essential rule of chess? And if so, must women also wear men’s suits, or are they allowed to wear dresses? Of course, people wear regular clothes when they are playing chess in other settings. But how do you know that they are not in violation of the rules, and that they are just getting away with it? Or do you assume without warrant that if they were indeed in violation, the rules would always be enforced against them?
Knowledge that Comes Apart from Observation Is Necessary
Without knowledge that comes apart from observation, observation itself can make no sense or communicate any information. The intelligibility and interpretation of observation presuppose knowledge about the objects of observation, and this knowledge cannot come from the act of observation itself.
That is, the intelligibility and interpretation of an experience is made possible by knowledge that comes apart from the experience. This knowledge may be something that is innate or something that is received by verbal instruction.
If the mind is totally blank, so that it does not even possess categories such as time, space, and causation, intelligibility and interpretation are impossible. In fact, if your mind is a blank, without any knowledge that comes apart from observation, your world will be to you as a whirlwind of sensations with no way to organize them or interpret them.
However, if a prior non-observational knowledge of reality is required in order to properly interpret observation about reality, this means that the order and meaning you observe is imposed on what you observe, and never derived from what you see. This is another way of saying that the meaning of what you observe is governed by your presuppositions.