Great thinkers like Aristotle, Descartes and Elon Musk have said that, in order to solve really hard problems, you have to get back to first principles. First principles in a designated problem space are so fundamental as to be self-evident; so true that no expert in the field can argue against them. They are atomic. Experts use them like building blocks to derive everything else that is worth knowing in the problem domain. In this paper, I propose that the first principle for all network defenders is to prevent high-risk material impact to the organization.