Explain to the principal that this statement cannot be either proved or disproved by application of the scientific method. If he/she disagrees, ask where you may find ANY peer-reviewed scientific paper that demonstrates this conclusion as a reproducable empiracle fact.
If he/she does agree, ask whether it is scientific to present non-scientific statements as scientific principles in a science text book.
Even better, have your daughter write an essay on why this "principle" is not scientific and why it renders the whole list of "fundamental laws of human ecology" a work of political philosophy with not one iota of scientific value.
Thank you. This is the type of input I'm looking for.