Source identified1
“Diversity repels; likeness attracts.”
The concise axiom is one premise in Boethius’s metaphysical argument: things are described as tending toward what is like them, not as a modern empirical rule about human attraction or relationships.
Source note: How Substances Can Be Good in Virtue of Their Existence Without Being Absolute Goods (De Hebdomadibus), preliminary proposition IX, H. F. Stewart / E. K. Rand 1918 edition, Project Gutenberg #13316. Kept as a historical metaphysical premise, not social-science evidence.
Source identified2
“There are many things which can be separated by a mental process, though they cannot be separated in fact.”
Boethius distinguishes conceptual analysis from physical separation: the mind can consider a feature on its own even when the thing and that feature cannot actually be pulled apart in reality.
Source note: How Substances Can Be Good in Virtue of Their Existence Without Being Absolute Goods (De Hebdomadibus), H. F. Stewart / E. K. Rand 1918 edition, Project Gutenberg #13316. The sentence introduces a metaphysical method by distinguishing mental abstraction from actual separation.