I generally agree with Rob and Richard on this.   Below is part of an

e-mail I sent to Tsachi.

My own view is that there are any number of reasons to be cautious

about any equation between a “reasonable belief that plaintiff

consented to the touching” defense in battery and reasonableness in

negligence law.   These include at least the following:

(a)        I believe that under the common law historically, and in most

American jurisdictions today, a defendant’s reasonable but false

belief that the plaintiff consented to the touching is not a consent

defense to battery, with the following very substantial caveat: it is

possible that the plaintiff did not intend to consent, subjectively, but

in fact engaged in conduct that a reasonable person would regard as

consent (and defendant did regard)– i.e., I think the correct (and

established) position on when consent has occurred for battery is

roughly the “objective” one that is found in contract law.    This

is what O’Brien v. Cunard can be understood as saying, although it is

sometimes read more broadly (perhaps even by the Resetatement (Second)

51 !).   Courts and commentators are even clearer about this point when

it comes to consent in other intentional torts, e.g., trespass to land;

(b)        There is little basis for taking the “reasonableness” of the

ordinary care standard of negligence law to be fundamentally epistemic

(even if epistemic errors are often plausibly brought in by litigators

on both sides, in particular cases).    The “reasonableness” of the

ordinary care standard in negligence law is fundamentally about whether

a defendant acted as a reasonably prudent or reasonably careful person

would have done; as I have argued elsewhere, this adverbial conjugation

of “reasonable” involves a specification of the level of prudence or

carefulness the fact finder should be measuring the defendant’s

conduct against, not a level of epistemic quality to measure the

defendant’s exercise of belief formation capacities against;

(c)        Reasonable mistake of belief in criminal law’s treatment of

self-defense looks quite different, initially, from what I described in

(a), but obviously tort differs from criminal law [but see Courvoisier

v. Raymond], and in any event the criminal law, excuse/justification

debate on how to treat mistaken belief in self-defense is a nightmare.

Ben Zipursky