What we observe is not nature itself, but nature exposed to our method of questioning. – Werner Heisenberg

What does it mean to know something? Are there conditions which must be met in order to claim that you know something? Finally, are there limits to what can be known about a particular topic or object out in the world? These, generally speaking, are the questions that epistemology is concerned with. Broadly defined, epistemology is the study of what it means “to know.” Epistemologists reflect on both the nature of knowledge and the limitations of the human ability to comprehend the details of the world.

Epistemology can be thought of as the heart of philosophy; some of the earliest philosophers started their enterprise by asking questions we’d today recognize as epistemological in nature. This makes sense when you think about it, as a deeper reflection on the exact nature of knowledge would provide a philosopher with a better means of categorizing what they learn through the process of philosophy.

But, why even ask these questions? Don’t we use knowledge every day? Isn’t it self-defeating to even ask questions like these?

What do you know?

Epistemology is likely responsible for philosophy’s appearance of supposed impracticality, as some of the considerations of epistemology affront common sense. This is because, in a manner of speaking, philosophers don’t like to take anything for granted. Philosophers often put to the microscope key assumptions that are unconsciously applied in most people’s daily lives. This can be seen in some of the most renowned writings in all of philosophy, like in Plato’s Allegory of the Cave and Rene Descartes’ Meditations on First Philosophy. Both works are iconic for inviting their readers to indulge in a peculiar and almost self-defeating sort of skepticism about reality.

In his allegory, Plato blatantly tells us that the world as we experience it is false. Like those who linger in the darkness of a cave, we cannot experience the true totality of the universe through our senses alone. Reflection, and more specifically philosophy, is required to get a better grasp of our unique circumstance within the universe. It is only through this kind of reflection that we can leave the metaphorical darkness of Plato’s cave.

Many, many centuries later, Descartes seems to take up Plato’s call, perhaps more rigorously than anyone before him. He isolates himself and, in his seclusion, seeks to rid himself of all his assumptions about the world to try to see reality for what it “really” is. Descartes’ exercise was skepticism in the most absolute sense — if his meditations were to lead him to the same truths his senses and experiences had already led him to, so be it. But, he likely felt he couldn’t be sure of that until he interrogated himself.

This seeming distrust of appearances and senses is something that comes up a lot in philosophy, and not just Western philosophy either. Those of you with passing knowledge of Buddhism might recognize that the goal of reaching nirvana requires one to let go of their misconceptions about themselves and the world to free themselves of the suffering that comes from a deep-rooted ignorance about reality.

While most contemporary philosophers don’t take skepticism to the extremes that Plato and Descartes did, there is a reason why both are still widely read and have influenced centuries of thought. There seems to be something that each is grasping at. But what exactly could it be?

Maybe it’s all in your head…?

For centuries, philosophers have had a nagging feeling that our minds tend to hide things from us from us and, oddly enough, they weren’t exactly wrong. Modern psychology and neuroscience has taught us a lot about ourselves, and despite how much we still don’t know, we do know some pretty fundamental things about our senses. One of the most important things we’ve learned is that our brains construct reality. This might seem obvious, but a lot of peoples’ intuitions are probably biased towards thinking our brains merely interpret reality (that was at least my intuition before taking a psych class). This isn’t true however as existing tendencies within the brain influence how reality is presented to us. This can be seen with optical illusions where our brains actually create false representations of phenomena, even after the illusion has already been demonstrated to us. Our personal expectations can also influence our experience of the world too, as seen with things like placebo and nocebo effects.

Since this isn’t a psychology blog I’m not going to go too far into the woods here, at least not in this post. But, suffice to say, since we all have different brains that are wired with subtle differences, even though we all exist in the same universe and are interacting in the same world, it’s entirely likely that I will never know exactly what reality is like for you. You might see more colors than me, or if you have any synesthetic tendencies you can perceive the color of sound. Even without exotic differences like these, as neuroscientist David Eagleman points out, we all live in our own heads and that’s the only reality that we know through our senses.

While this might be mind-blowing, what’s even more mind-blowing to me is that before modern psychology, philosophical, religious, and cultural systems sought to reign in things like cognitive biases without having direct knowledge of them.

Anyway, the point is that interrogation of common sense and, even interrogation of our senses has proven useful in progressing our sphere of knowledge. It’s this type of reflection that has indirectly paved the way for us to discuss things beyond our sense experience – like the electrons powering the very machine I’m writing this post on.