The first step of the process of demonstrating is gathering old knowledge to serve as the "required ground" (72 a 25) for new, scientific knowledge. In order to work and to do its job, the old knowledge must be "true, primary, immediate, better known than and prior to the conclusion" (71 b 21).
Some people think that all knowledge is demonstrative. Other people, like Aristotle, think that "not all knowledge is demonstrative" (72 b 18). Thus, the question is whether the old knowledge with the above five features is the product of a demonstration?
In Chapter Three Aristotle shows the following:
i. If old knowledge with five features is demonstrated,
ii. then old knowledge with five features is "circular" and bad.
Old knowledge that goes through the three step process of demonstrating and comes out "true, primary, immediate, better known than and prior to the conclusion" is impossible, like an unbroken egg from a kitchen blender. The required knowledge for science is like raw material.
The definition of raw material is "crude or processed material that can be converted by manufacture, processing, or combination into a new and useful product." The definition of crude is "existing in a natural state and unaltered by cooking or processing." The definition of processed is "treated or made by a special process esp. when involving synthesis or artificial modification."
The question is whether all knowledg is crude and unaltered or processed and modified? The anwer is that some knowledge is crude and some knowledge is processed. Aritotle writes, "Our own doctrine is that not all knowledge is demonstrative" and processed (72 b 19).
A person who says that all knowledge is demontrated "are faced with a difficulty" (72 b 33) that is "clearly frivolous" (73 a 17). Assenting to the universal, affirmative proposition that 'All knowledge is processed' is silly and frivolous, because of two reasons. First, every demonstration needs crude knowledge and no processed knowledge is crude knowledge. Therefore, no demonstration needs processed knowledge.
Aristotle supports the major and writes, "The necessity of this is obvious; for since we must know the prior premisses from which the demonstration is drawn, and since the regress must end in immediate truths, those truths must be indemonstrable" (72 b 20). Just as crude material is not processed, "prior, immediate and better known than" knowledge is not demonstrated. Immediate knowledge is not altered or filtered.
Accepting that all knowledge is processed is silly for a second reason. Aristotle explains, "Their theory reduces to the mere statement that if a thing exists, then it does exist" (72 b 33). The sad fact is, the person who agrees that 'all knowledge is processed' is the same person who must agree that 'a thing is because it is.'
Here is another silly argument: There is an animal in the Los Angeles zoo that is a kangaroo, and the animal is a mammal, because the animal is a kangaroo. (No, the animal is a mammal, because the animal has mammary glands.) In other words, to accept that all knowledge is processed is to accept some really ridiculous processes. Aristotle writes, "Convertible terms occur rarely in actual demonstration" (73 a 18). The logical tricks a person needs to employ in order to alter every single information bite are logical tricks that are rarely used in real life. Just as people cannot cut and trim every tree, people cannot process and demonstrate every known fact.