# I have a general question, totally clueless

1. Oct 16, 2012

### uperkurk

I just cut this from a university PDF file I found and just looking through. I understand absolutely nothing what is being said and I don't study physics in anyway. I can't even do algebra haha but I have a queston. Who invents this stuff? How can anyone remember all that stuff? How is it possible for someone to sit and think, then come up with such an equation or formula?

More to the point, how many different types of symbols are there in physics lol. Just inventing more and more by the looks of it.

#### Attached Files:

• ###### Untitled.jpg
File size:
21.3 KB
Views:
178
2. Oct 16, 2012

### mitchell porter

Some of the notation is just shorthand for calculations that are simple but tiresome when written out in full, e.g. multiplying and adding rows and columns of numbers in a certain order. Lots of "linear algebra" falls into that category. Then one step up from that would be calculus, which you can understand geometrically in terms of slopes and areas, but where the experience you need to read the symbols is more complicated than for algebra. Finally, you have the physical concepts that you need to read equations like those, like momentum, wavefunctions, groups of fields, because that's what the equations are ultimately talking about.

Experience also teaches you what's essential and what's inessential. For example, the central relation here is that an operator "C" applied to a two-part object (psi, psibar) gives the sum of two other two-part objects. The "i"s and "1/p"s are just numbers, details. It's just like how, if you were reading a sentence, you would know that the noun is the subject, and the adjectives modify the noun.

3. Oct 16, 2012

### SHISHKABOB

also, people don't just sit around and think up equations. All of our current knowledge is based off of what we already knew. It's like a big pyramid. Or maybe more like a big pile of sand that is getting more sand piled on to it. Something like that.

Long time ago, we started with the basics. Eventually, after lots of experiments and stuff, we've reached our current level. It's all built off of the stuff before it.

It's why kids can go to school, learn basic physics, and then eventually go on to make discoveries of their own when they become scientists.