By what is included or excluded, students are taught that they are part of or apart from the natural world. It just happens to be dead wrong. The same is true throughout the curriculum. A second principle comes from the Greek concept of Paideia. The goal of education is not mastery of subject matter but mastery of one's person.
Subject matter is simply the tool.
Much as one would use a hammer and chisel to carve a block of marble, one uses ideas and knowledge to forge one's own personhood. For the most part we labor under a confusion of ends and means, thinking that the goal of education is to stuff all kinds of facts, techniques, methods, and information into the student's mind, regardless of how and with what effect it will be used. The Greeks knew better. Knowledge of how to do vast and risky things has far outrun our ability to use it responsibly. Some of this knowledge cannot be used responsibly, safely, and to consistently good purposes.