Why is method so important for a thesis? Right now I am preparing a paper for my bachelor's degree thesis in computer science. I myself is an active programmer at work in my company and have created many programs till now.

I want to take some of my programs and take it for my thesis paper, my supervisor the program itself is good and I also can be promised a good grade too, but he still can't accept my paper because it does not have a Methodology in there. So my paper got rejected.

I wonder why the thesis really needs this methodology inside of the paper. But of course, I'm not that clueless to think that everything I make is always the original method I make myself. It just I always self-studying for programming for almost 5 years, so there might be someone method in my program but I just don't know what method I use or who make it.

But still, it kinda frustrating to get rejected just because there is no methodology mentioned... Why methodology is so important anyway?
Computer science, huh?

I think that the issue many forget with the name "computer science" (and that's why "informatics" as a word exists at all) is that it's not about computers. Well, that was harsh. It's not totally about those small silicon dies and such. It's about information processing. And it's about ideas.

Basically, "we wrote a program, hurdur" does not cut it. Even "we wrote a program, here is the github" does not cut it. "We got this cool result" is cool. But what most people would be interested in – on a large scale, in 10-20-100 years, – is not that you used an i7 chip. It's not that you wrote it in Python. It's the idea. The essence. The thing you write in methodology. Your very future readers would not care about your source code (even if it's available). They would be trying to implement your method in SuperCoolFunctionalNeuronQuantumSnake++#XXL that would be popular in 40 years. And what they'd read, is methodology.

tl;dr: Methods would persist, programming languages and even results would not.