I think your assumption that you should start with a foundation is wrong. Foundation is good, but the best way to it is to focus on other things. If you have a

I think your assumption that you should start with a foundation is wrong. Foundation is good, but the best way to it is to focus on other things. If you have a discipline A and a discipline B, and knowing A will help you a great deal with B, but B is totally unnecessary for A, it's natural to want to study A first. But this ignores the most important factor: everyday motivation. This is a much fuzzier thing than the dependency tree model, and it's natural to find it less attractive to think about. But it's real, and it's important. It's not enough to like the idea of conquering A. You have to find the process itself satisfying enough that it perpetuates itself. In practice, this often means learning B, being frustrated by your ignorance of A, but also excited enough to keep going. Then learning A once your studies of B have shown you the power and value of A. If there isn't anything that excites you enough to study it without putting in inordinate amount of willpower, don't feel bad. It's entirely the fault of institutions that educated you. The trick is to start with some real world problem that doesn't even seem respectable, but is exciting because it's real, and in the course of solving which you'll come in contact with other, "deeper" areas of knowledge.