section 4; sceptical doubts

In this section, Hume divides human reason and equiry into two parts, relations of ideas and matter of fact. Relations of ideas deal with the logical sense that are certain. For example, "that three times five is equal to the half of thirty", thus showing a relation between those numbers. Matter of fact is the other part to human reason which states that there cannot be a contradiction becasue its based on reality, cause and effect for that matter. If there is a contradictory than it cannot be conceived by the mind. Matter of facts are based on reality. For example, i know my friend is in France because she wrote me a letter. Hume states that matter of fact is known because of cause and effect. But then he questions, how do we know the principle of cause and effect? For example the idea of the pool table as discussed in class. If we hit the ball at a certain angle, how do we know that the other ball is going to move or that the ball we hit will just bounce back causing the other ball not to move? We do not know that the ball will move. Hume then says that cause and effect are based on past experiences. For someone who played pool will know the outcomes of hitting the ball.

How is it that if we rely on past experiences, we will know future outcomes? Are all cause and effect based on past experiences? If we do not have past experiences, how would we know what to do? Will we use then the idea of relations of ideas?