Hume

Also Hume mentions how he thinks that all complex ideas are formed from simple ideas. Then the simple ideas result to simple impressions. He also says that our imagination can only come from impressions we have had or experienced, so therefore our imagination is limited and we cannot imagine things that we never seen or heard, ect. However, he says that he can imagine a something he hasn't seen before but only because of previous impressions. For example, you can imagine a color you have never seen before but you have seen other shades of the color so you can form an idea and imagine what that certain color might be.