Epistemology is the philosophical study of what knowledge is and how we can come to have knowledge. It is a field of philosophy as old as philosophy itself, and epistemology underpins everything in philosophy, and not just philosophy, but everything that human beings do.
Thomas Hobbes and John Locke were English philosophers in the 1600s who were trying to understand what it is that the mind can understand about the external world. Their epistemology must be understood in the context of their time, the 1600s.
These was the early days of the scientific view of the world, and Hobbes and Locke were rethinking human perception to reflect the new scientific worldview. Because they were interested in science, their interest in epistemology centered on the questions of how we perceive objects in the world and form ideas about those objects.
They each had no doubt that the external world is knowable, is made of material bodies, and our minds are material or non-material depending on whether you’re listening to Hobbes or Locke. They saw the mind as something that takes in information through the senses. That’s why they’re called empiricists because they believed that all human knowledge comes from experience. But how Hobbes and Locke describe how we come to our ideas about the world are similar but have some significant differences.
Hobbes was an absolute materialist. Hobbes believed that absolutely nothing exists except matter. Everything that is in the external world is known to us as a material body and of course our minds are nothing but material. So, for Hobbes, this quite literally means that sense perception is caused by material particles from objects entering into a material body that are transformed through physics into ideas in the mind.
To understand Hobbes’s epistemology, let’s use the example of vision because it’s easiest to focus on that. Hobbes is saying that particles of light and physics has since verified that light is a particle (except when it’s a wave but let’s not go there right now). Particles of light come from the object and create an image in the body or a phantasm as Hobbes called it, a “phantasm,” or fancy, is something that is a representation of a real object.
Hobbes of course realized that trees do not enter the eyes and then the mind. A phantasm is an image of a tree created in the senses. Phantasms are appearances, they are not real objects. This is important because it is the phantasms, the appearances, that we deal with when we are thinking about objects. We do not deal with the objects themselves.
What happens, Hobbes says, is that the particles interact within our mind, assembling and disassembling appearances in our mind, constantly buffeted by new particles entering through the senses. What happens to appearances inside the human mind is fundamentally no different than what happens to rocks and sand on a beach.
One of the real problems with Hobbes’s overly simplistic conception is that he portrays us as nothing but passive observers. We are nothing but a perceiver and Hobbes is committed to this position because he insists that everything is material and everything is determined. That means that everything within the human mind is nothing but what is put there by the objects in the world.
What we call thinking is no more than reckoning, and reckoning is no more than reacting to the external world. And not even reacting, but caused by, determined by, the external world. For Hobbes, then, there is no actual human consciousness. Anything within our mind is absolutely nothing but passive activities that are completely determined by the external world. Things happen in the world, those things force particles into us, creating ideas in our minds. We react completely passively.
Hobbes’s View of perception creates several problems. He cannot explain human creativity. He cannot explain human consciousness and free will. For he most part, Hobbes’s epistemology is a dead end.
Locke’s view of perception and knowledge seems to better fit what we experience. Locke was developing his epistemology after the physics of Issac Newton. Newton’s physics had shown that objects in the world move in predictable ways according to natural laws. Locke wanted to find the natural laws that governed ideas in the mind.
Newton’s work had demonstrated that the human mind is powerful and creative, not purely passive as Hobbes believed. Locke also accepted, as Hobbes had not, that humans have free will.
Still, Locke shares some of Hobbes’s basic concepts. There are material objects out there in the world and these material objects cause things to happen within our material senses, but Locke then describes what happens in the mind with more detail than Hobbes had.
Locke attempted to describe human perception and how thinking about perception creates knowledge. Locke is asking these questions because impressions in the mind are not knowledge and Hobbes’s reckoning isn’t knowledge. Something more has to happen because simply my awareness that I’m perceiving an object is not knowledge, it’s just awareness.
Locke says that everything that is within the mind—anything and everything—is an idea. You need to lose your preconception of what “idea” means to understand fully Locke’s use of the term. For Locke, an idea is anything in the human mind—not just creative intellectual content.
For Locke, ideas can be broken down into two types. There are simple ideas and complex ideas. Simple ideas can be further broken down as simple ideas of sensation and reflection. Simple ideas of sensation are created by sense impressions.
When we perceive a white sheet of paper, that object produces in our minds the simple ideas of white, rectangular, and flat. So far, this is similar to Hobbes’s theory of perception.
Locke adds to this basic view of perception that the mind can combine simple ideas into complex ideas. When we perceive objects, ideas such as the height of the tree, the color of a tree, the width of the tree, and so on are combined in our mind into the complex idea of a tree.
Simple ideas of reflection are ideas that are still from the raw materials of our experience of the external world, but these are ideas from our mind reflecting on what it is that we are perceiving, so this is kind of similar to Hobbes’s reckoning.
The difference is that Locke sees us as, at least sometimes, actively thinking about and creating new ideas in our minds, but always exclusively from the simple ideas that are put in our minds through experience of the world.
Locke says that all simple ideas come from experience, but we can combine simple ideas in new ways. One example he gives is that we have experienced the simple idea of gold and the complex idea of mountain, and we can combine these ideas into the new idea of a gold-colored mountain. We can think this idea even though we have never experienced a gold-colored mountain. In this way, Locke is acknowledging the creative ability of the human mind more than Hobbes did.
Locke also goes beyond Hobbes by saying that the mind also has simple ideas of reflection. There is a very real cognitive difference between simply passively perceiving the world and then being aware of what you are perceiving. We humans have experiences beyond mere perception.
A motion detecting light can only perceive. It registers motion and clicks on. That’s all it can do. We can register motion, plus we are can be aware that we are aware and we can think and feel about what we are perceiving. Unlike the motion detecting light, we have experiences on which we can reflect.
That ability also empowers us to develop abstract ideas. We experience simple ideas of green in various objects and from these simple ideas we can create the abstract idea of greenness.
We similarly construct complex ideas, for example, taking all of our experiences of particular single trees and come up with a general, abstract, and also complex idea of what trees are. This is Locke’s answer to the old problem of universals.
Why do we have this universal concept of tree? Plato said it’s because we have knowledge of the perfect Form of Treeness, and that when we see an individual object, we recognize it as a particular example of a tree. Locke says, no, it’s the other way around. What happens is we experience many many, many trees and from our experiences of particular trees, through the mental process of abstraction we create a general idea of what trees are, emphasizing the similarities of the simple ideas that go into what trees are and eliminating the differences.
A significant implication of the empirical theories of Hobbes and Locke is that the world of our mental understanding is separate from the external world. We are not really experiencing the external world. We’re only observing the appearances in our mind that the senses give us.
Locke reluctantly admits that all we ever have to deal with in terms of the ingredients of our knowledge is what has placed in this box that he called the “camera obscura.” literally, “the black box.” All of our ideas are in the box of our mind.
This has a very profound implication, because if all that we know is in the box of our mind, how can we know for sure that what is happening there is an accurate reflection of what’s happening in the world? We can never step outside the camera obscura of our mind and compare this set of ideas to objects outside our minds.
It is inescapable that our sense perceptions are caused by the external world but we can never have a third party verification of what is the same and what is different between the impressions that are in our mind and the objects in the world.
How much of a problem that is has been debated ever since, but regardless of how substantial the problem is, this is the reality of how things are for us. And this is why epistemology remains an area of ongoing study in philosophy and related fields.