According to Hume, what is the ultimate source of knowlwdge? What is the difference between impressions and ideas? What is the difference between simple and complex impressions and ideas? In what ways...

According to Hume, what is the ultimate source of knowlwdge? What is the difference between impressions and ideas? What is the difference between simple and complex impressions and ideas? In what ways is the mind able to associate and relate ideas to one another?