A priori Knowledge?

Basically, and I will go into much greater detail later on, Hume says: We cannot infer from a pattern of events that the results will always be the same, even if we have observed it before - to do so requires an assumption about something we have not experienced. This is only knowable a posteriori. Is he right?

For Hume, there are two types of statements: a priori and a posteriori.

With the second type of statements, Hume argued against induction by saying that one cannot infer from a pattern of events that the results will always be the same, even if we have observed it before. To do so requires an inductive assumption that something will happen again that we have not already experienced. Because Hume is an empiricist, he says all we can know is what we experience. He then agues against cause and effect; if we do not experience the effect of a cause, we cannot say the cause will have that particular effect because we have not yet experienced it. We only know it a posteriori - after the fact. When a billiard ball hits another, we experience two separate events; one billiard ball moving, stopping, another one moving. We don't actually experience the 'cause' and 'effect' - all we experience are two events. Furthermore, Hume says if we observe a pattern of events that repeats itself, there is nothing different about our perception of one event and a latte,r similar event, except that it has been repeated. Hume says this is constant conjunction, not real cause and effect, since all we observe are two separate events that seem to be related. Furthermore, there is nothing that logically says that the event will continue to repeat itself with the same effects, only strong supporting evidence that it probably will. We don't actually experience the actual cause and effect part, only two separate actions that are in constant conjunction.
The first type of statements, a priori knowledge, are statements like 'all bachelors are unmarried' and '2+2=4'. These statements are necessarily true, since it logically follows that bachelors = unmarried people and '2+2=4". We understand these logical statements a priori. However, they don't really tell us anything about the world, because they only tell us about concepts, not real things. With the statement 'an equilateral triangle has 3 equal sides', we understand that this is a logically true statement by definition. However, there is no such thing in real life, so they cannot be used to prove anything in the real world. We could change the definition of bachelors, and have it equal something else - it doesn't really matter. These are conceptual, logical exacts, but they are not present in the world. Since they cannot prove anything in the world, they cannot prove anything a posteriori. Since they cannot be used to prove these a posteriori, a posteriori statements cannot prove anything in the world, since they are not grounded in anything logical - only other statements a posteriori.

 

Hume is incredibly insightful on this point. The problem with induction is clear to any observer.

I was wondering about this a few days ago. I was thinking the following: If six geese walk through the room that are white, why do people say it is probable that the next goose walking through will be white as well? I know only that these six geese have been white - to extend this to the next goose requires a knowledge of that goose and of why these qualities apply to it. This doesn't seem to be capable of being derived from experience.