The design and development of Moodle is guided by a particular philosophy of learning, a way of thinking that you may see referred to in shorthand as a "social constructionist pedagogy". (Some of you scientists may already be thinking "soft education mumbo jumbo" and reaching for your mouse, but please read on - this is useful for every subject area!)
This page tries to explain in simple terms what that phrase means by unpacking four main concepts behind it. Note that each of these is summarising one view of an immense amount of diverse research so these definitions may seem thin if you have read about these before.
If these concepts are completely new to you then it is likely that these ideas will be hard to understand at first - all I can recommend is that you read it carefully, while thinking about your own experiences of trying to learn something.
This point of view maintains that people actively construct new knowledge as they interact with their environment.
Everything you read, see, hear, feel, and touch is tested against your prior knowledge and if it is viable within your mental world, may form new knowledge you carry with you. Knowledge is strengthened if you can use it successfully in your wider environment. You are not just a memory bank passively absorbing information, nor can knowledge be "transmitted" to you just by reading something or listening to someone.
This is not to say you can't learn anything from reading a web page or watching a lecture, obviously you can, it's just pointing out that there is more interpretation going on than a transfer of information from one brain to another.
Constructionism asserts that learning is particularly effective when constructing something for others to experience. This can be anything from a spoken sentence or an internet posting, to more complex artifacts like a painting, a house or a software package.
For example, you might read this page several times and still forget it by tomorrow - but if you were to try and explain these ideas to someone else in your own words, or produce a slideshow that explained these concepts, then I can guarantee you'd have a better understanding that is more integrated into your own ideas. This is why people take notes during lectures, even if they never read the notes again.