David Hume: Copy principle

Today we will talk about David Hume and his copy principle. According to Hume, our mind consists of what he calls “perceptions,” which can be divided into two categories: impressions and ideas. Impressions are the raw, direct experiences we receive through our senses—such as the taste of a lemon or the sound of music. Ideas, on the other hand, are the faded copies of these impressions that remain in our minds after the original experience is gone.
Hume makes an important distinction from Locke’s philosophy here. Locke believed that secondary qualities—such as color, taste, or smell—were projected onto objects by the observer. Hume disagreed, asserting that we cannot have an idea of something we have never experienced. For example, if you have never tasted a pineapple, you cannot truly imagine its taste. Only after experiencing it can you form an idea of what it is like.
Hume takes his empiricism further than Locke with what he calls the “copy principle.” This principle states that all ideas are merely copies of real-world impressions. Our minds do not create new elements but only rearrange existing ones.
This principle also gives us a way to filter meaningful ideas from meaningless ones. If an idea does not correspond to a direct impression from the real world, it is either distorted or completely meaningless. Let’s take the example of a banana: we have seen and touched bananas, so we can verify our idea of a banana by comparing it to a new one. However, when it comes to concepts like God, we lack direct impressions that match the idea, making it difficult to determine its validity.
Despite this strict empirical approach, Hume acknowledges that we can form new ideas by combining existing ones. If we have seen the color blue and a banana before, we can imagine a blue banana—even if we have never encountered one in reality.
Hume’s method of breaking down complex ideas into their simpler components allows us to test their legitimacy. If an idea cannot be traced back to direct impressions, we should question its validity. Science, according to Hume, should be built upon verifiable sensory experiences rather than abstract speculation.