It will not do to memorize the formulas, and to say to yourself, “I know all the formulas; all I gotta do is figure out how to put ’em in the problem!”
Now, you may succeed with this for a while, and the more you work on memorizing the formulas, the longer you’ll go on with this method – but it doesn’t work in the end.
You might say, “I’m not gonna believe him, because I’ve always been successful: that’s the way I’ve always done it; I’m always gonna do it that way.”
You are not always going to do it that way: you’re going to flunk – not this year, not next year, but eventually, when you get your job, or something – you’re going to lose along the line somewhere, because physics is an enormously extended thing: there are millions of formulas! It’s impossible to remember all the formulas – it’s impossible!
And the great thing that you’re ignoring, the powerful machine that you’re not using, is this: suppose Figure 1 – 19 is a map of all the physics formulas, all the relations in physics. (It should have more than two dimensions, but let’s suppose it’s like that.)
Now, suppose that something happened to your mind, that somehow all the material in some region was erased, and there was a little spot of missing goo in there. The relations of nature are so nice that it is possible, by logic, to “triangulate” from what is known to what’s in the hole. (See Fig. 1-20.)
And you can re-create the things that you’ve forgotten perpetually – if you don’t forget too much, and if you know enough. In other words, there comes a time – which you haven’t quite got to, yet – where you’ll know so many things that as you forget them, you can reconstruct them from the pieces that you can still remember. It is therefore of first-rate importance that you know how to “triangulate” – that is, to know how to figure something out from what you already know. It is absolutely necessary. You might say, “Ah, I don’t care; I’m a goodmemorizer! In fact, I took a course in memory!”
That still doesn’t work! Because the real utility of physicists – both to discover new laws of nature, and to develop new things in industry, and so on – is not to talk about what’s already known, but to do something new – and so they triangulate out from the known things: they make a “triangulation” that no one has ever made before. (See Fig. 1-21.)
In order to learn how to do that, you’ve got to forget the memorizing of formulas, and to try to learn to understand the interrelationships of nature. That’s very much more difficult at the beginning, but it’s the only successful way.