Short answer. Section 5 of Rule 6 explains: a negative defense specifically denies a material fact the plaintiff alleged; an affirmative defense admits the plaintiff's allegations hypothetically but raises new matter — like fraud, prescription, or payment — that would still bar recovery.
What the law says
A negative defense is the specific denial of the material fact or facts alleged in the pleading of the claimant essential to his or her cause or causes of action.
Rule 6, Section 5 — Defenses. Read the full provision →
What the law says
An affirmative defense is an allegation of a new matter which, while hypothetically admitting the material allegations in the pleading of the claimant, would nevertheless prevent or bar recovery by him or her.
Rule 6, Section 5 — Defenses. Read the full provision →
Negative defenses: denying the facts
A negative defense, per Section 5(a), is the specific denial of the material fact or facts alleged in the pleading of the claimant essential to their cause or causes of action. In other words, this is where the defendant says the plaintiff's factual story is wrong — disputing the very facts the plaintiff needs to prove to win, rather than accepting them and arguing some other legal reason recovery should be barred. A negative defense therefore puts squarely at issue whether the plaintiff can actually prove the facts underlying the claim, rather than conceding those facts and arguing about their legal consequence.
Affirmative defenses: 'yes, but...'
An affirmative defense, per Section 5(b), works differently: it hypothetically admits the material allegations in the plaintiff's pleading, but raises a new matter which would nevertheless prevent or bar recovery. The section lists examples: fraud, statute of limitations, release, payment, illegality, statute of frauds, estoppel, former recovery, discharge in bankruptcy, and any other matter by way of confession and avoidance — essentially conceding the plaintiff's version of events while introducing a separate legal obstacle to their claim.
Affirmative defenses can also raise dismissal grounds
Section 5 further clarifies that affirmative defenses may include grounds for dismissing the complaint outright — specifically, lack of jurisdiction over the subject matter, another action pending between the same parties for the same cause, or that the action is barred by a prior judgment. This folds what used to be separate motion-to-dismiss grounds directly into the affirmative defenses a defendant raises in the answer itself. That folding matters because it means a defendant does not need a separate, free-standing device to put these threshold objections before the court — raising lack of jurisdiction over the subject matter, a pending prior action, or a prior judgment as an affirmative defense accomplishes within the answer what used to require filing something apart from it.