gmark 77 is offering a Stone fallacy.
When Negatives
- Mathematics and logic: Negatives are routinely proven.
- Example: “There is no largest prime number.” This was proven by Euclid.
- Example: “√2 is not a rational number.” This is a classic proof by contradiction.
- Formal systems: In structured environments with clear rules (like chess, programming, or geometry), you can prove that something cannot happen or does not exist.
When Negatives
- Empirical claims about the real world: It’s often difficult or impossible to prove a universal negative.
- Example: “There are no unicorns anywhere in the universe.”
- You’d need exhaustive evidence of every possible location, which is impractical.
- Philosophical or theological claims: Proving the nonexistence of abstract entities (e.g., God, ghosts) is often considered impossible because the burden of proof lies with the person making the positive claim.
Why the Confusion?
The phrase “you can’t prove a negative” is often misused. It’s true that
some negatives are hard or impossible to prove, especially universal claims without boundaries. But in logic, science, and law,
negatives are proven all the time—especially when framed correctly.