# What it Means to Understand Something When I say that I understand how the curvature of space and time affects the motions of planets, even in other solar systems I may never have heard of, I am not claiming that I can call to mind, without further thought, the explanation of every detail of the loops and wobbles of any planetary orbit (this would effectively be a form of *prediction*, which is not what we are after). What I mean is that I understand the theory that contains all those explanations, and that I could therefore produce any of them in due course, given some facts about a particular planet. Having done so, I should be able to say in retrospect, ‘Yes, I see nothing in the motion of that planet, other than mere facts, which is not explained by the general theory of relativity.’ So in a sense we can quantify our understanding of a system based on how much of its behavior we could **derive** or **generate** based on our current knowledge. Note this is not simply asking how much of it's behavior we could *predict*. For instance, consider a forest of maple trees. Our problem is to determine when their leaves will change colors and fall off the trees. Now if we simply memorized that in our experience the leaves tend to fall off around the start of October (in our little New England town), that would allow us to make a correct prediction on average - given that we are in that little New England town under average conditions. But we have absolutely no *understanding* of what makes the leaves fall! What if we go to a different town that is further north? What if the temperature stays above 70 degrees all the way into November? What if we are in a town in Australia? What if we are on the moon inside of a large terraformed enclosure? Without an [explanation](Explanations.md) of what causes the leaves the to fall we will be completely at a loss of understanding what will happen in those scenarios. We can see that even in the above example, part of understanding is a result of being able to "drill down" and derive certain principles and facts from your current knowledge. But we must also note that *just because you understand a theory does not mean you understand everything it can explain*. With a very deep theory, the recognition that it explains a given phenomena may itself be a significant discovery requiring independent explanation. --- Date: 20240821 Links to: [Fabric of Reality](Fabric%20of%20Reality.md), pg 12 Tags: References: * []()