The problem with slogans

Coleman Hughes writing fot Quillette has an interesting piece on deepities.
The word deepity, coined by the philosopher Daniel Dennett, refers to a phrase that seems true and profound but is actually ambiguous and shallow. Not to be confused with lies, clichés, truisms, contradictions, metaphors, or aphorisms, deepities occupy a linguistic niche of their own. The distinguishing feature of a deepity is that it has two possible interpretations. On the first reading, a deepity is true but trivial. On the second, it’s false but would be mind-blowing if it were true.

“No Human Being Is Illegal”

On one reading, this claim is undeniable. Legality is a concept that applies to actions, not people. People can be male or female, introverted or extroverted, blind or sighted; but they cannot be legal or illegal. Like the claims, “no act of kindness is red” and “no prime number is lethargic,” the claim, “no human being is illegal,” is simply a category error.

The term “illegal immigrant” is similarly misleading. It’s not the person that is illegal (whatever that could mean) but the act of moving across a border without following certain procedures. Since the claim “no human being is illegal” is neither true nor false, it literally cannot be denied—that is, you can no more argue that “some human beings are illegal” than you can argue that “some prime numbers are lethargic”—and because the claim is undeniable (in the literal sense), it can sound plausible, and even obvious.

But the second reading of this deepity asserts something extremely controversial: everyone should be able to go anywhere on Earth with no legal or procedural barriers; every border should be fully permeable; strangers should be able to occupy your property—after all, no human being is illegal, and strangers are still human beings when they’re on your property. Needless to say, even advocates of open borders would not endorse this view in full. But if the view were ethically correct, then it would have profound implications for property law, the existence of nation-states, and the very concept of personal space.