A claim creates an obligation. If it is false, identify the error. If its premises fail, expose them. If the evidence is weak, show the weakness. If the reasoning breaks, locate the break.
Ad hominem removes the obligation. The proposition enters. Attention moves to the person carrying it.
What kind of person would say this? What have they done before? Who associates with them? What do they want? Why are they angry? Are they credible? Are they respectable? Are they one of us?
The claim remains untouched.
The original burden is epistemic: determine whether the claim survives examination. The substitute burden is social: determine whether the claimant deserves examination at all.
The substitution works because people are easier to attack than propositions. A proposition has premises, evidence, definitions, causal claims, and implications. A person has a biography. A contradiction. A failure. An affiliation. A motive. A bad sentence. A friend. A former belief. A present enemy.
None of it has to falsify the claim. It only has to make listening expensive.
Now the claimant faces a trap. Defend the argument and the accusation hangs unanswered. Defend the self and the argument disappears. Either response advances the diversion.
The audience stops asking whether the proposition is true and starts asking whether association with the speaker is safe. Agreement acquires reputational cost. Curiosity resembles sympathy. Examination becomes endorsement.
The attack has altered the price of considering the claim.
It no longer needs to prove the argument wrong. It only needs to establish that the wrong kind of person made it. From there, truth value becomes secondary.
The speaker can be arrogant instead of correct. Or arrogant instead of wrong. The mechanism works either way. Character attack is compatible with any truth value. That is what makes it useful.
An argument may survive scrutiny. A person can always be made dirtier. So the dirt accumulates while the proposition waits.
Nothing has been disproved. Nothing has been established. The object of judgment has been replaced.
Then the residue travels. The next appearance of the claim inherits the reputation of the last person who carried it. The next speaker inherits the suspicion.
Soon the proposition no longer arrives as a proposition. It arrives as evidence about the person willing to repeat it.
Refutation is no longer necessary. The argument has become a character test. The test reproduces itself.
