Knowledge and understanding both require some critical thinking skill. But they aren’t the same thing and cultivating some understanding of how they differ is a worthy critical thinking exercise in itself.
Here I’ll be concerned with propositional knowledge, knowledge of truths, as opposed to knowledge by acquaintance (knowing your friend) or know how (knowing how to ride a bike). Also, I’ll be focused on understanding things like views, ideas, arguments and theories. Understanding people is a much more ambitious undertaking and it is bound to be limited in various ways even among the most intimate of friends. To be a person is in part to be a subject and this involves a degree of exclusivity. No other subject can directly share your own subjective experience. Still, while this looks like a reason for thinking we can never completely understand another person, many of us are quite skilled at developing and conveying quite rich and insightful understanding of themselves and others. Very impressive examples can be found among biographers, memoirists, novelists and therapists. Beyond these professional roles, I’d like to submit that the aspiration to better understand a person is a basic element of personal love.
Now let’s start with some evidence. We all know that water boils at 100C, but a good understanding of the physics behind this fact is not so widespread. So, we can have knowledge in the absence of understanding. We can also have understanding in the absence of knowledge. I’ve been working steadily to understand Christine Korsgaard’s philosophical views about agency and identity for a while. If I keep at it, maybe just maybe, I’ll know whether they are true in a few years. The evidence of these two cases shows us that knowledge and understanding aren’t the same thing. We could cite further examples but it quickly becomes clear that you can have either one without the other.
We’ve gained some knowledge already, but we remain a good ways from understanding just how knowledge and understanding differ. It will help to think about how the aims of knowledge and understanding differ. Knowing aims at true belief. Understanding is often a crucial step towards knowing. But understanding itself doesn’t require truth. I can come to understand Korsgaard’s philosophical views pretty well even if they aren’t true.
Our substantial but limited understanding of people reveals a further interesting difference between knowing and understanding. Knowing, in a certain sense, is a yes or no affair. You either know that 7*8=56 or you don’t. But while I think I now have a decent understanding of Korsgaard’s views on agency, I wouldn’t yet characterize my understanding as very good and it remains far from expert. Understanding often comes in degrees. (Note that knowledge by acquaintance and know how also come in degrees. You can know your friend sort of well or very well. Likewise for knowing how to ski or ride a skateboard.)
It is the truth component of propositional knowledge that is a binary yes or no affair. A proposition is either true or not true. The sentence “Russ likes philosophy” is true if what is says fits the way things are. Otherwise it’s false. A clear and complete claim either fits the way things are or it doesn’t. Where a claim is ambiguous or vague, it’s not clear how the claim represents the world, so truth is harder to ascertain. But once we get onto a clear representation of the some aspect of the world, that representation either fits the way the world is or it fails to.
Knowledge also involves justification. In order to know that Russ rides bikes, you’d have to have good reasons for thinking this is true (these are not hard to find). Justification does admit of degrees. Your reasons for believing something can be good, really good or not so great. What degree of justification is required for knowledge is a complicated and contentious matter among philosophers. Some hold the view that being justified in believing something is a matter of having a reason that gives you complete certainty. Indeed good reasons in some realms, like math or geometry, do seem to rise to the realm of certainty. But this doesn’t generalize. For if knowing requires complete certainty, then you don’t know where your car is parked most of the time, and this seems to miss perfectly good ordinary attributions of knowledge. I am justified in believing that my car is parked where I left it 20 minutes ago. But I can’t be certain it hasn’t been stolen in the past five minutes. In lots of ordinary every day cases, I can have a reason that is good enough for knowing in the ordinary sense of the term, but that falls well short of certainty. Still the binary of truth and falsity remains at play. I may have the appropriate kind of justification for knowing where my car is and yet not know in the case where my belief is false because my car has just been stolen.
Understanding, as we’ve noted, doesn’t require truth. A historian of science may understand Aristotle’s physics quite well while knowing full well that it is false. Being un-tethered to the binary of truth and falsity, understanding admits of degrees. These aren’t the sorts of degrees you can helpfully measure on a numerical scale. But you can completely miss the point of a theory, sort of get the basic idea, have a decent grasp on it, comprehend it pretty well, or develop some real expertise. These are ordinary and useful ways of describing our degrees of understanding or misunderstanding.
The next step in better understanding understanding would be to develop some theoretical models of understanding. Then we’d want to test the various models of understanding for clarity, logical coherence and good fit with available evidence. Maybe then we could claim to know what understanding is. But for now, perhaps we should be content with having pushed our understanding of understanding forward by a few degrees.