Does a patina on a knife prevent rust? Before I begin, I think it's worth mentioning that I know little about chemistry and even less about knives. 

My question is this, having seen many people talk about how patinas work and the best ways of applying them and which ones are best etc., It seemed to me like people just assumed that they work, presumably because they heard someone else do it, and them from someone else and so forth but that doesn't always make it true. If anyone has any idea If there is any reasoning behind this and if there any flaws behind the logic in it that would be greatly appreciated. 

I don't exactly want to ruin or change my new knife for no reason. I assume people might think that this works similar to the thin oxide coating on aluminium, but my guess is that the corrosion acts like it would on any metal and slowly "eat away" at it. 

So, simply, does it work?
In this case, the use of the word patina is a little misleading. Patina refers to the oxidation film on bronze or aged polish. I assume that you mean that the knife is coated with a substance.

First, when steel oxidizes, the iron oxide that forms does not stick well and will flake off the surface. This would not be useful for a knife since the edge will become dull quickly.

Second, if the knife is made with stainless steel, it does not need to be coated to prevent rust, only keep reasonably dry. Some stainless steel will actually rust since it was not properly formulated. Very few knifes are made of other metals since stainless steel is reasonably cheap.