Aristotle on Demonstrative Knowledge (12-Feb-2004)

The passage opens with Aristotle saying "All intellectual learning arises from pre-existing knowledge". For the purposes of this essay I use the following definitions:

With these definitions in mind, the opening statement of the passage suggests that any knowledge we acquire (learn) must be:

So far as it goes, this seems reasonable: if we have a set of knowledge (according to my earlier definition), then any facts deduced from a valid argument based on this knowledge must also be knowledge. However, this begs the question of whether the process of combining and building goes downwards forever, or whether there is a kind of fundamental knowledge beneath which no "earlier" knowledge exists?

For Aristotle, the answer is yes: "we must already have some capacity" which allows us to acquire this foundational knowledge (it is acquired, not innate). The capacity to which Aristotle refers he calls "nous", which is sometimes translated "intuition", and relates to the ability he believes we have that allows us to infer a foundational truth based on our sensory experience - once we have had a certain type of experience repeated a number of times, "the perception is of a universal", i.e. we are able to acquire foundational knowledge: "The mind is so constituted as to be capable of this."

An example of this might be for me to infer, having seen various circles, the foundational truth that "circles are round".

One problem with this type of argument is that it says that we can "know" something based on a subset of all the available empirical evidence, and it's not exactly clear at what stage we can make the jump and say "I've seen enough now to formulate a new foundational truth". Aristotle seems to be saying that "nous" is more than just an inferential process, but some mechanism which is capable of perceiving a universal truth in a kind of "aha" moment, which would preclude flawed inferences being made. But it is not entirely clear (to me anyway) how this works.

Another problem with this is that it doesn't deal with contingent truths, e.g. that my wife went shopping today. It would seem that I ought to be able to "know" this, but it's not easy to see how it would build on previous knowledge, or stand as a foundational truth itself.


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