Epistemology is a debate which roots to ancient Greece. One side of the debate was the rationalists who argued that we learn about the world through our mind and what is already in it (a-priori). The other side of the debate is the empiricists who argued that we learn about the world through our senses. A much more refined explanation of empiricism compared to the definition given by the Greek philosopher Aristotle, was suggested years later by the English physician John Locke. Locke defined the mind as being a blank piece of paper filled by the experience of our senses. He defined simple ideas as ones that cannot be further simplified and can be only perceived through the senses and complex ideas as ones that are comprised by relating simple ideas one to another and applying them to different cases (abstraction). Locke also defined primary qualities as the real qualities of anything and secondary qualities as the qualities we assign to anything after experiencing it with our senses. Locke’s empiricism is a complete contradiction to the rationalism theory which relies on the a-priori and isn’t much more or less convincing, just another theory that doesn’t give a sufficient answer to many questions. The very core of Locke’s empiricism which states that the mind is blank fails to explain how same experience results in different knowledge, the notion of complex ideas becomes very problematic when talking about its definition, and the failure of Locke to properly explain substance in his terms of primary and secondary qualities undermines the strength of his approach to epistemology.
First, Locke suggests that the mind is “a blank slate of white paper void of all characters” (Palmer, 76) and that this paper is filled with words by experience. So the mind is compared to blank paper and experience is the writer. Now, consider the scenario of a classroom filled with students listening to their teacher for 40 minutes. Let’s assume that all of the students see and hear the teacher clearly, would everyone receive the same grade in a quiz taken in the end of that lesson? Probably not… Is there anything else then in charge of knowledge besides sensual experience? Maybe everyone has a different writer (a-priori) typing on their piece of paper and the experience is their ink?
Another problem with Locke mind-to-paper analogy arises when he defines complex ideas in a way that contradicts his empiricism. When Locke defines complex ideas as a comparison between several simple ideas, he treats the ability to compare as something inherent we already possess, leaving our paper minds not completely blank! In further explaining complex ideas, we take complex ideas (which in turn are comprised of simple ones) and apply the similar ideas to different cases. This reasoning basically says that from a present experience we can derive future experience! For the purpose of understanding the fallacy here, let’s consider ethics as a complex idea that is comprised of a number of simple ideas like pain, happiness, depression, pleasure, danger etc… when we think of ethics, we can basically take a number of cases which we never experienced and already have knowledge (secondary quality in specific) about them being more or less ethic. This gives rise to a question of how do we get from what is to what is ought to be without a-priori?
Besides having some serious trouble with his definition of terms, Locke fails to use his own terms when talking about substance. According to Locke, we perceive secondary qualities from experience. Even though secondary qualities may not match primary qualities, they are still there. We experience, we get knowledge (according to Locke). Why then, when it comes to substance, we experience it a lot and frankly all the time but do not even have a secondary quality of what it is (again, according to Locke)?? This is a big failure of Locke to correctly apply his own terms consistently.
To conclude, Locke’s analogy of the mind to a blank piece of paper does not always satisfy what really happens in the world. Locke’s definition of complex ideas cannot be explained without priori, what he actually tries to avoid the most in his theory. Lastly, he basically shoots himself in the foot when talking about substance which is something we experience all the time and yet cannot comprise the slightest idea of what that is. Maybe a better approach to epistemology would include a-priori in Locke’s theory, since it is needed to explain much of his terminology.