From: Robert Stevens <>
To: Wright, Richard <>
Date: 17/06/2009 08:09:08 UTC
Subject: RE: reasonable mistake and the reasonable person

In the context of self defence we have a prima facie conflict of rights.

My right to bodily safety gives me a privilege to use reasonable force in

defending myself if you lunge at me with a carving knife. In striking the

balance between your right and mine, my belief that force is necessary

must be reasonable. It is not enough, as it would be in the criminal law,

that is is honestly held.

That the tort itself is, unquestionably, one of strict liability does not

conflict with this. If I kiss you, honestly and reasonably believing that

you consent when you do not, there is a battery. There is no conflict of

rights involved in such a case, and no question as to the scope of any

special privilege I may have by virtue of my own right to bodily safety.

In Vincent, prima facie, although completely blameless, the defendant’s

actions in intentionally tying up to the dock constituted a trespass as

they no longer had a licence after the withdrawal of consent by the dock

owner. Normally in such a case of intentional trespass the dock owner

would have the privilege to untie the boat’s cables, but this privilege

did not arise because of the emergency, so that if the cables had been

untied the dock owner would have been committing conversion, and

potentially liable for the full value of the ship if lost.  A judge at

dockside would not have restrained the boat’s owner from tying up, but the

privilege to do so was qualified, so that compensation was payable

calculated by reference to the loss suffered from the use. The defendant

was only within the privilege, and not committing a wrong, if compensation

representing the loss suffered was paid. The cause of action is not,

therefore, trespass, but there would be a trespass if the money for the

loss suffered was not paid. Here the defendant’s actions are justified not

merely excused.


> Along with Prosser, I disagree with the old cases and the Restatement

> position that a defendant who makes a reasonable mistake in self defense

> should not be liable for a battery.  I think those cases are poorly

> reasoned and were decided at a time when it was thought that to hold the

> defendant liable would label the defendant as being at fault and/or mean

> that the defendant should not have defended himself against the reasonably

> (but mistakenly) perceived attack.  Vincent has it right: this is SL, not

> fault.


> There of course was no mistake in Vincent, so the mistaken self-defense

> cases are inapposite.  The defendant there knew that he was trespassing on

> and damaging another's property without consent.


> The mistaken self-defense cases are an exception to the general position

> regarding mistaken trespass.  The results have been more mixed in cases

> involving mistaken defense of others.  As the Restatement indicates, the

> liability is clear in mistaken trespass to land or chattel cases and

> mistaken recapture of property cases, and also in cases involving mistaken

> belief that there is consent.


> ________________________________


> From: Stephen Sugarman []

> Sent: Tue 6/16/2009 5:48 PM

> To: Simon Douglas

> Cc: Wright, Richard; Tsachi Keren-Paz;

> Subject: Re: reasonable mistake and the reasonable person




> Where there is a battery claim and the defendant asserts self-defense but

> there was a reasonable mistake by the defendant (who thus injured an

> innocent party), the defendant wins according to the ALI Restatement and

> some old cases.


> See Section 63 Restatement of Torts (Second) (1965), especially comment h,

> illustration 7. The leading cases on this point are Courvoisier v.

> Raymond, 23 Colo. 113, 47 P. 284 (1896) and Crabtree v. Dawson, 119 Ky.

> 148, 83 S.W. 557 (1904). In the Reporter's Notes, Prosser wonders whether

> the defendant ought not bear the costs of his mistake.


> In my very long article on the "necessity" defense (in which I attack the

> VINCENT decision and the Restatement's endorsement of it), I use the

> rejection of "strict liability" by the Restatement and these cases for

> what could be termed trespass to the person as an example of how US law

> seems inconsistent.


> Steve Sugarman


> ___________________________________


> Simon Douglas wrote:


> Ranson v Kitner 31 Ill App 241 (1888) is a good example - the defendant

> shot the  claimant's dog, thinking it was a wolf, but was found liable in

> trespass.


> Simon Douglas


> ___________________________________


>  "Wright, Richard" <> writes:


> Not quite the answer to the question you pose, but an answer that moots

> your question.


> I am traveling so I don't have access to my copy of the Restatement

> Second, but I believe that it states the general position in US law that

> the mistaken trespasser is liable despite the reasonableness or good faith

> of the mistake, unless the mistake was intentionally or negligently

> induced by the plaintiff.


> ________________________________


> From: Tsachi Keren-Paz []

> Sent: Sun 6/14/2009 5:05 PM

> To:

> Subject: reasonable mistake and the reasonable person


> Dear colleagues,


> Can anyone refer me to discussion (in either case law or literature) of

> the question whether reasonableness in the context of a reasonable mistake

> (for example mistake about the claimant's consent to touching in battery)

> is to be judged by the same or different considerations as reasonableness

> in the context of standard of care in negligence?


> Any thoughts of whether the tests should be the same/similar/different?


> Best wishes

> Tsachi





Robert Stevens

Professor of Commercial Law

University College London