Law of Identity
Horse. Zebra. Similar, but different. The Law of Identity is based on the ability to make distinctions with our language—something difficult to do if we're hamstrung by underdeveloped observational skills or crippled by a limited vocabulary.
For example. If you have the desire to have a practice of nonsymptomatic families availing themselves of care designed to maintain their health or promote wellness, calling them "patients," which comes from the Latin meaning "to suffer," blurs the distinction. Oh, they may begin care as patients, but at some point (if all goes according to plan) they're no longer suffering. If you want more these non-suffering regulars, you'll want to call them something other than patients. (i.e. clients, practice members, participants, etc.)
This is this and that is that. Success does not flow toward ambiguity, vagueness or those who are lazy with language. Rigor displayed here pays off later, but it's a distinction lost on many.