Peter Maas wrote: > Learning is investigating. By top-down I mean high level (cat, > dog, table sun, sky) to low level (molecules, atoms, fields ...).
Aha. So you must learn cosmology first then. I don't think so. ;) I don't know if you really think that you learn things top down, but I doubt that you do. I know I don't. It's very rare that I have a good understanding of the overall workings of a system before I start to learn details. As I learn little details here and there, my understanding of the entire system is gradually growing and changing. Sometimes, a minor detail might completely change my overall picture of a system. In my experience, software designs developed by people who lack a good hands-on understanding of the details in a software system rarely work. We can't know the "top" properly unless we know a lot about the "bottom". Do you think children learn to speak by arriving at some kind of general understanding of grammer before they learn individual words? :) People typically don't learn things top down, and I think there are good reasons for that. Regarding software development, Bertrand Meyer said something like this: "Top-down design doesn't work, because real software systems have no top." His view of Object-Oriented development is that it's a process where we go from that which is known to us, to that which is (still) unknown. It might go up or down, but we start with what we know, and gradually expand our understanding into new territories armed with what we have learnt so far. Analysis or decomposition is only half of logical thinking. Synthesis or composing parts into entire systems are just as important, and we can't just do one part first, the other after, and then be done with it. We are all different intellectually, both genetically and by training and education. Some people find it easier to grasp theories, and others need more tangible examples. For each person, the useful approach will probably depend on the previous experience in that particular field, or in related areas. > And to know the lowest levels is not strictly necessary for > programming. I have seen good programmers who didn't know about > logic gates. People might be "good programmers" in some sense, but they will make mistakes if they don't understand the underlying mechanisms. This doesn't mean that you need to understand all details down to the quantum mechanics level, but if you see programing as a purely "logical" activity, without regards for the technical implementation, you will run into plenty of problems. One classical trap is to fail to understand how floating point numbers are represented in computers. Other common problems among people who lack a technical understanding for computers is that they fail to see how and why their solutions use up different amounts of resources, be it memory, CPU time or whatever. I've also often seen confusion because people fail to understand the distinction between other logical and an internal representations, such as cunfusion over the fact that a date which looks like eight digits don't use eight bytes in the database, and frustration over the fact that the database doesn't allow you to store 0000-00-00 in a date field. It's just the same as with cars. You can be a fair driver without knowing anything about mechanics, but the more you know about how the car works from a mechanical and physical point of view, the easier it will be to understand why it behaves the way it does, and the less likely you are to make mistakes when unusual things happen. Just as you can learn how cars behave from experience, or from advice from others with experience, without understanding the underlying mechanisms, you can learn programming this way. We have learned things that way for thousands of years. I don't think it's optimal though. Robert Pirsig's "Zen and the Art of Motorcycle Maintenance" covers this subject. But we all have to start somewhere, and it's never to late to learn something new. Curiosity and an open mind often means more than formal education. Some people with a very "good" education seem to believe that the thing they've learnt is all that matters, and they will fall into other traps. There is always another perspective that might give us a new insight. -- http://mail.python.org/mailman/listinfo/python-list
