What is understanding? Is it the same thing as knowing or is it different? In this short article, I want to gently explore this idea without getting philosophical.
When we were school kids, we used to recite poems written by eminent authors without missing a beat. Of course, most of the time we did not understand the meaning of the poems. In other words we knew the poems by heart, but did not understand them. This is natural and quite common.
So what is the difference between knowing and understanding?
Knowing is having information. We can know facts. For example, I know that Chennai is the capital of Tamil Nadu. Thus, knowing provides answers to “what”. In order to know something, we don’t need to have a “grasp” of it. I might know that “E = mc2” without being able to explain the intricacies such as what it implies about the universe. Thus knowing is somewhat shallow.
Understanding is deeper than knowing. It is grasping the meaning, relationships, causal links, and implications. It enables us to answer “why” as well as “how”. When we understand something, we can explain and apply it to solve problems – not just recall. For example, I understand why a ball thrown up falls down – the impact of gravity on any physical body.
When I understand something, I can explain it in different ways and recognize it immediately when I see it in unfamiliar situations. When I understand that “ice floats on water”, I can answer questions such as “why do lakes freeze at the top first?” and “Will ice float on petrol?”. I can’t do this when I just know something; at best I can repeat it.
Here are some reasons as to why understanding is deeper than knowing:
1) When we understand something we construct a mental model and this allows us to reason about it.
2) Most of what we understand are based on sensory experience. For instance, I understand when someone says the music is “loud”, because I have personally experienced the same.
3) A subtle distinction is what is called “metacognition” – knowing what I know and what I don’t.
4) Most importantly, “understanding” empowers us to do “counterfactual reasoning”. I can reason about hypotheticals – “what would happen to the economy if interest rates increase?”
This brings us to an important question: “Do LLMs understand?”
I guess the correct answer is that they don’t – at least not in the way we humans do. Then how is it they answer many questions “intelligently” and “correctly” too? The key to understanding this behavior is pattern recognition. LLMs have been trained on an enormous amount of data and so when they come across a new problem, they are able to recognize the shape. They are able to generalize and seem to be able to solve problems that appear similar, but without the finer inner model that humans seem to build and use.
I know this topic is deeply philosophical and perhaps even we humans don’t really understand understanding. No doubt this is an active area of research and one day we will be able to precisely and formally define understanding. Will LLMs reach that level of understanding? Only time will tell!
Have a nice week ahead!
Knowledge is about facts while understanding is about reasoning as you have stated. Is mental model an intricate web of patterns? Your last sentence this topic is deeply philosophical and perhaps even we humans don’t really understand understanding” is the answer!