Why Understanding Beats Knowledge

>> Ask you that same question in a different way and you have no idea. Never heard of it. This is why whiteboard interviews are hard – questions that you know, but out of context

In my experience this is true. I "test" my friends on these and most of them always screw up an answer to the questions I asked them just a couple of days ago when the question is slightly different but the underlying principle is the same. This is also why I spend hours on a question I get an answer to easily. Because it's important to understand the principle rather than getting the right answer. You can also conduct this test. The simplest and the most basic test is to ask someone what "binary search" is. Obviously, every developer knows what it is but when you ask them to apply binary search in a slightly different context(pick up any medium binary search question on Leetcode, Hackerrank etc) they will fudge it up. I get the hate "trivia" algo interview questions get on HN. However, I just love them because I have always loved "puzzles"

Does not apply to tech interviews.

So I'm totally on board with everyone knowing something about the liberal arts and trying to expand your world outside your traditional scope.

But I think "understanding" can mean just making connections within a single tech field, even without involving liberal arts. For example, a grade school math problem: "Assume the earth is a perfect sphere with radius 6378 km, and you have a piece of string just long enough to reach all the way around the earth's equator at the earth's surface. How much longer would your string have to be to make a perfect circle exactly one meter above the earth's equator at every point?"

The answer is 2(pi) meters. That's true for any spherical planet of any size -- that's what it means for the derivative of 2(pi)(r) with respect to r to be 2(pi). That is sometimes not the first thing people think of though, because of the grade-school context they associate with this problem....

Closish, but not quite how I see it.

Having information does not imply having knowledge of it. For example, an engineer may not know which material can withstand a given environment (temperature, corrosion, pressure, etc) but they may be able to look it up in a book and select the appropriate material.

Knowledge is similar, except it's within the mind. For example, an engineer may know that the thermal coefficients for steel and concrete are similar, so the expected deformation under temperature change should be similar. But this doesn't mean that they necessarily understand why these two materials have similar coefficients, only that they do.

Understanding is a matter of cognitive appreciation of the underlying situation and is built around the parameters of a situation. For example, someone drowning understands that they need to grab something buoyant in order to breath. It's built on a base of knowledge, but it doesn't necessarily imply that they have knowledge of the complete situation. Even in science or software, there are things that one can know without understanding. Personal example: There was once a bug in ruby when built from source. I was tracking down a bug in production and I was unable to replicate it locally. So I finally got someone to shell into prod and run three lines of code for me. That code crashed even though it worked fine on literally every other computer I tried it on, including staging. I knew that the issue was with the production server, but I didn't understand why. It took further work to go from knowledge to understanding.

Wisdom is squishy. It correlates with experience, yes, but there are other factors that play into it as well. A child can be wise and choose not to associate with, say, a gang not because they've experienced it before, but because of something else. An inner reflection of the dangerousness of the situation and the courage or inner resolve to avoid it.

Here is a GIF demonstrating the tangent line as a point traverses a curve: https://s3-us-west-2.amazonaws.com/courses-images/wp-content...

The "pencil" (the short line representing the tangent) is green when positive, black when zero, and red when negative. Note that when it is black/zero, the "pencil" line is flat. This occurs at both local maxima and minima.