What Is Epistemology? Pt. 2: Types of Knowledge

What is epistemology? What types of knowledge exist? What is justification? Are there other epistemologies?

In this second post on epistemology, I’ll be talking about modern notions of defining knowledge.

What is knowledge?

Epistemology fundamentally begins with the definition of knowledge. The reason this is the case is because any comprehensible statement regarding facts or ideas about the world requires that the question of what knowledge is be answered, even if only on a very basic level. Essentially, in order to make comments about what is or is not true, or how something works, there are aspects of reality that need to be privileged. Thus, defining knowledge helps us understand how and why we come to the facts and ideas which we favor.

Although philosophers’ conceptions of knowledge have differed vastly across time, the one thing that is apparent is that there are likely different ways we can conceive of knowledge. For example, to know a fact about something is different than “know-how,” or the knowledge of knowing how to do something. Unfortunately, at times it can seem like determining all the types of knowledge that exist is a task which yields no definitive answers due to the many dimensions by which we can choose to define knowledge. I’d argue, though, that the task is still worthwhile as it helps sharpen the boundaries between the types of knowledge that we are able to identify. It’s worth noting that this issue of choosing how to define knowledge is something present within many cultures and not just in philosophy. For example, those of you who know Spanish might recognize that the verb conocer denotes one type of knowledge and the verb saber another type of knowledge.

For contemporary Western philosophers, there are generally a handful of types of knowledge that are considered important.

Declarative knowledge or “knowledge-that:” In philosophy, declarative knowledge refers to descriptive statements, called propositions, which describe some aspect of reality. Declarative knowledge is also sometimes called “descriptive” or “propositional” knowledge for this very reason. Statements like “roses are red” or “there are frogs in France would count as examples of declarative knowledge. In many cases, declarative knowledge is expressed as propositional statements stating that it is the case that something is/has/does X.

A number of epistemologists posit that it’s not possible to “know” false propositions, so by some accounts, a declarative statement like “the moon is made of cheesewould not be declarative knowledge. Great chunks of epistemology have focused on the exact nature of declarative knowledge, and in many cases, this type of knowledge is a point of primary concern for epistemologists.

Procedural knowledge or “knowledge-how:” This is knowing how to do something, a skill. The question in philosophy is to what degree knowledge-how differs from knowledge-that. The answer to this question might seem obvious, but certain examples can make you think twice about the distinction between these two types of knowledge.

To illustrate the point, think about the instructions for driving a vehicle. The act can be broken into the following knowledge-that propositions: “I know that one turns the key in the ignition to start a car,” “I know that one then puts their foot on the gas pedal to accelerate,” etc. To what degree exactly are these knowledge-that statements distinct from knowledge-how? It’s clear that the knowledge reflected in these propositions articulate the procedures of driving. That is to say, someone who uses the facts contained in these knowledge statements will drive; yet there’s an inkling that this is mere conceptualization – being able to utter these statements, and even being able to understand their meaning, is not the ability to drive itself. Interestingly, the field of psychology discusses these differences in terms of declarative and procedural memory. The distinction between these types of memory is real as amnesia will often affect knowledge about information and facts while leaving skills and abilities intact.

Knowledge by acquaintance: This is knowing something via first-person experience or familiarity via direct interaction. The contemporary debate regarding this form of knowledge concerns whether or not it can be considered a valid category of knowledge. This might seem ridiculous, after all, we use our senses to “know” things all the time. But there are conceptual limitations to this category which make it questionable as a distinct type of knowledge. The main issue is that it’s not clear what objects knowledge by acquaintance can apply to and, even if being generous, it seems to have very limited applicability.

To give you a sense of the limitations I’m talking about, consider that some major advocates for this category of knowledge insist that we can’t be acquainted with physical objects — like the keyboard I’m typing from right now. Even though I’m experiencing tactile sensations by typing, and I can see the keyboard’s color from the corner of my eyes, a proponent for this type of knowledge would say that these sensations aren’t details of the object itself. As you’ll recall in the previous epistemology post, I told you that our minds construct reality. So, perhaps if I were a different type of organism, the sensory data I’d receive would be entirely different because I’d have a different mind. Even as a human, the sensations I’m feeling now could be experienced if I were hallucinating or dreaming.

Basically, the only thing that’s necessary for me to experience the sensation of touching a keyboard is for specific parts of my brain to be stimulated in a certain manner. That could happen by touching the keyboard in real life — which I’m hopefully doing now — or it could happen if I were plugged into the Matrix and fed a simulation of the sensations I’d feel while typing an epistemology blog post. In the latter case, there’s no knowledge by acquaintance because there’s no object. But from my brain’s point of view, all cases are the same — whether I’m dreaming about writing this blog post, writing it in the Matrix, or writing it for real, the same parts of my brain are stimulated. The object doesn’t have to be there and, in fact, if I’m committed to knowing through acquaintance alone, I’ll never be able to tell if the object is there since all I have to go off of are sensations.

What this comes down to is that, at best, our knowledge by acquaintance is only of the sensory data from our minds and not of objects in the world itself. Knowledge by acquaintance can still exist but, as its proponents point out, its sphere of relevance is limited. This doesn’t mean that a proponent of this type of knowledge believes we can’t know anything about reality; it just means other considerations are necessary to substantiate knowledge about things in the world.

Another limitation which is often mentioned is that knowledge by acquaintance can’t distinguish between similar appearances. The analogy of a “speckled hen” is often the go-to thought experiment for philosophers, but who cares enough about hens to count speckles? Luckily, you can easily apply this concern to other analogies. Imagine that my friend Brian uses knowledge by acquaintance to say “I know there are 4 jelly beans in this jar.” That’s fair as Brian, like most of us, can probably recognize the appearance of 4 individual objects without counting. But say that the number were 40 or 400, what would happen then? There will eventually come a point where Brian can no longer “recognize” how many beans are in the jar by simply looking at it; however, it seems rather arbitrary that knowledge by acquaintance has a supposed cutoff. Some proponents are okay with this cutoff, but to other philosophers, it creates doubt about the consistency of acquaintance knowledge as a necessary category of knowledge.

Outside of these three types of knowledge, there are tons of other proposed types of knowledge, like those centering around “Wh-” questions (who, which, when, etc.). However, a great deal of contemporary epistemology and even older philosophy in the Western tradition focuses on declarative knowledge. Declarative knowledge itself can be broken into other types of knowledge and applied to both individuals and groups. In later posts, we’ll cover these distinctions in greater detail.