Mugger. Excuse me a moment, would you sir? I'm a bit short on cash.

Bentham. Sorry.

Mugger. (notices a utilitarian pin on Bentham's lapel) But you're a utilitarian, right?

Bentham. Indeed, I am an Act Utilitarian: I believe I ought to perform an act if that act would produce more utility than any alternative act.Footnote ¹

Mugger. That's grand. How about you give me ten pounds?

Bentham. Now, as an Act Utilitarian, I would happily part with ten pounds if I were convinced that you would bring more utility to the world with that money than I would. The trouble is I know I would put the money to good use myself – whereas you, I surmise, would not.

Mugger. Fine. I suspected as much. But what if I sweeten the deal? If you don't give me the money, I'll cut off a finger!

Bentham. You're threatening me?!

Mugger. Wait, no. I'm not threatening you. That would be illegal. I'm saying that, if you don't give me the money, I'll cut off my finger.

Bentham. Why on earth would you do that?

Mugger. I am a Deontologist. I am true to my word.

Bentham. (notices a deontological pin on Mugger's lapel) I see. But then, if you don't mind my asking, why did you promise to cut off your finger?

Mugger. Look, what happened happened. Let's cut to the chase. I have diagrammed our situation:

(unfolds a large poster)

Bentham. You had that diagram ready all along?

Mugger. You, at the first node, have a choice between giving me ten pounds (going up) or keeping the money (going down). If you keep the money, I have a choice at the second node whether or not to cut off my finger. The thick line denotes that I would, in fact, do so.

Bentham. (nods)

Mugger. Here's the thing: there is, clearly, more utility in me keeping my finger than in you keeping your measly ten pounds. So there would be more utility in the world if you gave me the money than if you didn't.

Bentham. I think you should just keep your finger.

Mugger. And go back on my word? No. (chuckle) What if everyone did that? Besides, what should matter to you, as an Act Utilitarian, is that I would cut off my finger – not whether I should.

Bentham. Fair enough. But, even so, I worry that giving you the money would set a bad precedent, encouraging copycats to run similar schemes.

Mugger. Don't. This transaction will be our little secret. You have my word.

Bentham. (not entirely convinced)

Mugger. You're playing hardball? (sigh) All right, let's make the deal sweeter still: If I don't get the money, I'll cut off two fingers.

Bentham. This conversation has sure taken a regrettable turn.

Mugger. I'm sure going to miss those fingers.

Bentham. (pause) Okay. Fine.

(hands over £10)

Mugger. Excellent.

(pockets the money and folds, carefully, the poster)

Bentham. I somehow feel I got mugged.

Mugger. Not at all. You made the world a better place.

Mugger. (sees Bentham) It's been a while, hasn't it?

Bentham. Oh, … hi.

Mugger. What's the matter?

(notices Bentham's unadorned lapel)

Where's your pin?

Bentham. Alas, wearing it in public became too costly.

(notices Mugger's hand)

What happened to your hand?

Mugger. Funny you should ask. It turns out that some so-called ‘Act Utilitarians’ are Act Utilitarian in name only. To cut a long story short, fingers were … cut. And it hurt a lot. And having the fingers sewn back on cost a lot. So – while I'm back to ten – I find myself, once more, a bit short on cash.

Bentham. Sad. Very sad to hear. But, before you reattempt your scheme, I'd like to share some news. I'm no longer an Act Utilitarian. I'm now a Rule Utilitarian: I believe I ought to perform an act if that act is required by a rule that prescribes a possible combination of everyone's acts that produces more utility than any other combination.Footnote ²

Mugger. I like this! It feels almost deontological.

Bentham. And, crucially, I'm no longer susceptible to your finger scheme, since the best combination of our acts didn't include my giving you money. A plausible moral theory shouldn't lay one open to that kind of exploitation. I wonder why I never saw this fault in utilitarian thinking. But no matter – the theory is fixed now.

Mugger. May I suggest a collaboration?

Bentham. Sure.

Mugger. There's this new course called Effective Benevolence: Morality Made Easy.Footnote ³ If I took this course, I would become an effective altruist just like you.

Bentham. Sounds great.

Mugger. The trouble is the course costs ten pounds. And here's where you could help out. Would you contribute ten pounds to let me realize this dream?

Bentham. Tempting.

Mugger. I've diagrammed our new situation:

(unfolds another large poster)

At the first node, you have a choice between giving me the money (going up) or keeping it (going down). If you give me the money, I have a choice between using that money to take the course (going up) or keeping it for myself (going down). Surely, me becoming an effective altruist is better than you keeping your ten pounds. Hence a rule prescribing your giving me the money and my using that money to take the course is a rule that prescribes the best possible combination of our acts.

Bentham. So I should give you the money.

Mugger. (noticeably impressed by Bentham's deduction) I truly cherish working with sharp minds.

Bentham. Wait – why is one line thicker than the others?

Mugger. Oh, that denotes that I wouldn't take the course. If you gave me the money, I would in fact keep it for myself.

Bentham. You left that datum out of your pitch.

Mugger. I don't see how it would be relevant for a Rule Utilitarian. Your giving me the money would be part of the best possible combination of everyone's acts no matter whether I would take the course. What should matter to you is that I could do so – not whether I would.

Bentham. Suddenly, it seems that it may have been a mistake to assess rules by their being adopted by everyone. There will be deviants. I now think I'm a Partial-Compliance Rule Utilitarian: I believe that I ought to perform an act if that act is required by a code of rules that is optimal in the sense that its internalization by the overwhelming majority would be best.Footnote ⁴

Mugger. (clears throat) I have an announcement to make. I'd like to make it known that, if a code of rules were internalized by the overwhelming majority, I would internalize it too.

Bentham. You would?

Mugger. At that point, I feel, it would be antisocial not to.

Bentham. So, when I assess different codes of rules, I should assess their being internalized by the overwhelming majority including you?

Mugger. That's right.

Bentham. But, since the optimal code of rules won't actually be internalized by the overwhelming majority, you won't actually internalize that code of rules.

Mugger. Well, yeah.

Bentham. So, even though the optimal code of rules would, plausibly, prescribe me giving you the money and you taking the course (since that code is optimal given that it's internalized by the overwhelming majority including you), you would not take the course.

Mugger. Uh-huh.

Bentham. I'm getting second thoughts about Rule Utilitarianism all together.

Mugger. Very well. So you're going back to Act Utilitarianism? In that case, let me offer a deal–

Bentham. Let me cut in right here. I now think I'm a Self-Harm-Discounting Act Utilitarian: I believe that I ought to perform an act if that act would produce more utility than any alternative act with utility measured so that saving people from harm does not count towards utility if these people can save themselves.Footnote ⁵

Mugger. This is a major departure from standard Act Utilitarianism.

Bentham. True. But, with this modification, the theory is immune to your finger scheme. Since you could still avoid cutting off your finger in case I don't give you money, that avoidable harm does not count towards overall utility.

Mugger. Could you stick around a bit? I need to run a quick errand.

Bentham. No worries.

Mugger. And, just to double-check, when you say that harms don't count if people can avoid them themselves, you mean harms that people can still avoid themselves? That is, you aren't a Retrospective Self-Harm-Discounting Act Utilitarian, believing that you ought to perform an act if that act would produce more utility than any alternative act with utility measured so that saving people from harm does not count towards utility if these people can save themselves or could have saved themselves if they had chosen otherwise in the past?

Bentham. No – I'm not a monster. We have all made mistakes. The moral agent looks forward. If I found you drowning in a pond, I should save you regardless of whether you went in freely.Footnote ⁶

Mugger. Great, just as I thought. Stay put. I'll be back in a jiff.

Bentham. What took you so long?

Mugger. Sorry, I had to make a binding, unalterable arrangement with a thug, who will cut off my finger if you don't give me ten pounds. I've diagrammed our current predicament:

(unfolds a third poster)

As before, you have a choice at the first node between giving me ten pounds (going up) or keeping the money (going down). If you don't give me the money, the thug has a choice at the second node whether or not to cut off my finger – and the thug would do so, no matter what I do. So, if you don't give me the money, I can't avoid being harmed. If you don't give me the money, the thug will cut off my finger. So my finger is in your hand, so to speak. (chuckle)

Bentham. Funny you should say that. While you were away, I had some time to reflect on morality. I now think I'm more of a Mugging-Restricted Act Utilitarian: I believe that I ought to perform an act if that act would produce more utility than any alternative act and, in addition, it wouldn't make me vulnerable to blatant muggings, threats, or blackmail.

Mugger. I don't want to rag on your new philosophy, but where's the theoretical purity of standard Act Utilitarianism? This theory is soiled with muddy, ambiguous terms. What, more precisely, is a ‘mugging’?

Bentham. I know one when I see one. And your latest scheme, I'm sure, is one.

Mugger. That's not a very satisfying answer.

Bentham. I'm afraid it will have to do for now.

Mugger. Also – and I hate to say this – your latest theory is, more than a little, ad hoc.

Bentham. Well, what it lacks in beauty, it makes up in expense minimization.

Mugger. Look, even if your theory tells you what you ought to do, it lacks explanatory power. A moral theory may tell us not only what ought be done but why it ought be done. Why settle for less?

Bentham. If I find an unmuggable version of utilitarianism with more explanatory power, I'll let you know.

(A Thug approaches.)

Mugger. This is disappointing.

Bentham. I'm not going to give you more money.

Mugger. Okay. Fine. I'll cut off three fingers if–

Bentham. Sorry, but here I must cut you off.