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电车难题之思


我们翻译这篇文章的理由


      伦理思想实验充其量是构建简化模型的不可靠方式,这些模型相当不完美地映射到我们所经历的世界上。所以,我们是否应该放弃使用它们作为道德洞察力的来源?
  ——田阳光


👇


电车难题之思


作者:James Wilson 

译者:王宇琪 & 张松

校对:李蕾

编辑:张煜成


The trolley problem problem

电车难题之思

Are thoughts experiments experiments at all? Or something else? And do they help us think clearly about ethics or not?

思维实验真的是实验吗?它们到底能否帮助我们清晰思考道德?

Much recent work in analytic philosophy pins its hopes on learning from imaginary cases. Starting from seminal contributions by philosophers such as Robert Nozick and Derek Parfit, this work champions the use of thought experiments – short hypothetical scenarios designed to probe or persuade on a point of ethical principle. Such scenarios are nearly always presented context-free, and are often wildly different from the everyday contexts in which ethical sensibilities are formed and exercised. Most famous (or infamous) among these are ‘trolley problems’ – thought experiments about the permissibility of causing the death of a smaller number of people to save a larger number from a runaway trolley (or train). But there are thousands more, with some papers containing as many as 10 separate cases.

最近许多分析哲学的工作都寄希望于对假想案例的研究。从罗伯特•诺齐克(Robert Nozick)和德里克•帕菲特(Derek Parfit)等哲学家的开创性贡献开始,他们倡导使用思维实验——设计简单的假设场景以探索或论证某种伦理原则的观点。这些场景通常没有语境的来龙去脉,而且往往与形成和实践伦理人情的日常环境大相径庭。其中最著名(或说最臭名昭著)的是“电车难题”思维实验,指在造成最小伤亡的情况下,从失控的有轨电车(或火车)前拯救更多人的可行性,此外还有数千种不同思想实验,有些研究甚至包含数十个单独案例。


While thought experiments are as old as philosophy itself, the weight placed on them in recent philosophy is distinctive. Even when scenarios are highly unrealistic, judgments about them are thought to have wide-ranging implications for what should be done in the real world. The assumption is that, if you can show that a point of ethical principle holds in one artfully designed case, however bizarre, then this tells us something significant. Many non-philosophers baulk at this suggestion. Consider ‘The Violinist’, a much-discussed case from Judith Jarvis Thomson’s 1971 defence of abortion:

虽然思维实验与哲学本身一样古老,但近代哲学却赋予了它独特的价值。纵使假设场景毫不现实,对它们的论断也被认为对现实世界的处事原则有着广泛的影响。这预设了如果你能在一个精心设计的案例中证明道德原则的某一点是正确的,不管其多么离奇,它都告诉了我们一些重要的东西。许多非哲学家对这一建议不以为然。让我们来看看“小提琴家”思维实验,这是朱迪思•贾维斯•汤姆森(Judith Jarvis Thomson)1971年为堕胎辩护时提出的一个备受讨论的案例:


You wake up in the morning and find yourself back-to-back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist’s circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you: ‘Look, we’re sorry the Society of Music Lovers did this to you – we would never have permitted it if we had known. But still, they did it, and the violinist now is plugged into you. To unplug you would be to kill him. But never mind, it’s only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you.’

某天早上醒来,你发现自己和一个不醒人事的小提琴家背靠背躺在床上,一个著名的昏迷的小提琴家,患有致命的肾病,音乐爱好者协会查阅了所有可用的医疗记录,发现只有你有合适的血型可以救他。因此,他们绑架了你,前一晚,小提琴家的循环系统被接入了你的循环系统,这样你的肾脏就可以同时从你们二者的血液中过滤毒素。医院负责人现在告诉你:“听着,我们很抱歉音乐爱好者协会对你做了这样的事——如果早知道的话,我们是不会允许它发生的。但是,木已成舟,现在小提琴手已经和你‘血脉相连’了。拔掉这些管子就等于杀了他。但没关系,只要9个月。到那时,他的病就会痊愈,可以安全地与你的身体分开了。”


Readers are supposed to judge that the violinist, despite having as much right to life as anyone else, doesn’t thereby have the right to use the body and organs of someone who hasn’t consented to this – even if this is the only way for him to remain alive. This is supposed to imply that, even if it is admitted that the foetus has a right to life, it doesn’t yet follow that it has a right to the means to survive where that involves the use of an unconsenting other’s body.

读者应该能作出这样的判断,尽管小提琴家和其他人一样有生命的权利,但他没有权利未经同意使用他人的身体和器官——即使这是他活下去的唯一方式。这意味着,即使承认胎儿有生命权,也不能证明胎儿有留下来的权利,因为这涉及到在未经同意的情况下使用别人的身体。


From the perspective of philosophers, the point here is clear, even if Thomson’s conclusion is controversial. In the few instances I tried to use this thought experiment in teaching ethics to clinicians, they mostly found it a bad and confusing example. Their problem is that they know too much. For them, the example is physiologically and institutionally implausible, and problematically vague in relevant details of what happened and how. (Why does the Society of Music Lovers have access to confidential medical records? Is the operation supposed to have taken place in hospital, or do they have their own private operating facility?) Moreover, clinicians find this thought experiment bizarre in its complete lack of attention to other plausible real-world alternatives, such as dialysis or transplant. As a result, excellent clinicians might fail to even see the analogy with pregnancy, let alone find it helpful in their ethical reasoning about abortion.

从哲学家的角度来看,这里的观点十分明确,即使汤姆森的结论颇具争议。当我在少数情况下,试图用这个思维实验向临床医生讲授伦理时,他们大多认为这是一个糟糕且令人困惑的例子。他们的问题是知道的太多了。对他们来说,这个例子在生理学和制度上都是不可信的,而且在具体情形和如何发生的相关细节上也含糊不清。(比如,为什么音乐爱好者协会可以获得保密的医疗记录?手术应在医院进行,还是他们有自己的私人手术设施?)此外,临床医生发现这种思维实验的怪异之处在于,它完全忽视了现实世界中其他可行的替代方案,如透析或者移植。因此,优秀的临床医生甚至可能找不到这一案例与怀孕的可比之处,更不用说发现它有利于堕胎的伦理合理化了。


Thought-experiment designers often attempt to finesse the problem through an omniscient authorial voice that, at a glance, takes in and relates events in their essentials. The voice is able to say clearly and concisely what each of the thought experiment’s actors is able to do, their psychological states and intentions. The authorial voice will often stipulate that choices must be made from a short predefined menu, with no ability to alter the terms of the problem. For example, the reader might be presented with only two choices, as in the classic trolley problem: pull a lever, or don’t pull it.

思维实验设计者常常试图通过作者上帝般的全知叙事来巧妙地处理问题,这种叙事让人只需一眼,就能从本质上理解并关联事件。它能够简明清晰地表明思维实验中的每个人物能够做什么,以及他们的心理状态和意图。作者的叙事通常会规定,必须从一个简短的预设列表中选择,不能去改变问题的条件。例如,读者可能只有两种选择,就像经典的电车难题一样:拉杆,或者不拉杆。


All this makes reasoning about thought experiments strikingly unlike good ethical reasoning about real-life cases. In real life, the skill and creativity in ethical thinking about complex cases are in finding the right way of framing the problem. Imaginative ethical thinkers look beyond the small menu of obvious options to uncover novel approaches that better allow competing values to be reconciled. The more contextual knowledge and experience a thinker has, the more they have to draw on in coming to a wise decision. Ethical thought experiments work best when those who read them are willing to go along with the arbitrary stipulations of the author. 

所有这一切使得思维实验的演绎与现实案例的伦理论证截然不同。在现实生活中,对复杂案例进行道德思考的能力和创造力,体现于找到正确的方式来构建问题。富有想象力的伦理思考者能够超越简单的预设选项列表,发现能更好调和对立价值观的新方法。一个思考者拥有的背景知识和经验越多,他们在作出明智决定时需要的考量就越多。而当阅读这些伦理思维实验的人愿意接受作者武断的规定时,其效果也就越好。


What would the world need to be like for thought experiments to be a good way of making progress in ethics? I’ll canvass two suggestions: first that the thought experiment is a kind of scientific experiment, and second that it is an appeal to imagination. As we will see, on either reading, thought experiments are highly fallible, and we should be circumspect about taking them to provide insights into real-world ethical problems.

我们需要改变什么,才能让思维实验成为道德进步的好方法?我将讨论两点看法:首先,思维实验是一种科学实验,其次,它是对想象的呼吁。正如我们将看到的,在任何一种理解中,思想实验都很容易出错,我们应该谨慎地使用它们来提供对现实伦理问题的洞见。


If thought experiments are – literally – experiments, this helps to explain how they might provide insights into the way the world is. But it would also mean that thought experiments would inherit the two methodological challenges that attend to experiments more generally, known as internal and external validity. Internal validity relates to the extent to which an experiment succeeds in providing an unbiased test of the variable or hypothesis in question. External validity relates to the extent to which the results in the controlled environment translate to other contexts, and in particular to our own. External validity is a major challenge, as the very features that make an environment controlled and suitable to obtain internal validity often make it problematically different from the uncontrolled environments in which interventions need to be applied.

把思维实验视作字面意义的“实验”,将有助于解释它们可能如何提供洞察世界的方式。但这也意味着,思维实验将继承广义上的实验所面临的两大方法论挑战,即内部效度与外部效度。内部效度指一个实验能够对议题中的变量或假设提供无偏性检验的程度,而外部效度指受控实验环境中的结果在多大程度上能转化为在其他环境、特别是我们的现实环境中的结果。外部效度是主要的难点,因为使环境受控、实现内部效度的实验特征,往往冲突于落实实验结果的不受控真实环境,这种不同正是问题所在。


There are significant challenges with both the internal and the external validity of thought experiments. It is useful to compare the kind of care with which medical researchers or psychologists design experiments – including validation of questionnaires, double-blinding of trials, placebo control, power calculations to determine the cohort size required and so on – with the typically rather more casual approach taken by philosophers. Until recently, there has been little systematic attempt within normative ethics to test variations of different phrasing of thought experiments, or to think about framing effects, or sample sizes; or the extent to which the results from the thought experiment are supposed to be universal or could be affected by variables such as gender, class or culture. A central ambiguity has been whether the implied readers of ethical thought experiments should be just anyone, or other philosophers; and, as a corollary, whether judgments elicited are supposed to be expert judgments, or the judgments of ordinary human beings. As the vast majority of ethical thought experiments in fact remain confined to academic journals, and are tested only informally on other philosophers, de facto they are tested only on those with expertise in the construction of ethical theories, rather than more generally representative samples or those with expertise in the contexts that the thought experiments purport to describe.

思维实验的内在效度和外在效度都面临着重大挑战。我们有必要比较医学研究者或心理学家审慎的实验设计(包括问卷验证、双盲试验、安慰剂控制、确定所需同期群大小时采取的效能计算等等)与哲学家相对更随意的实验方法。直到最近,规范伦理学中一直很少有系统性研究来考察思维实验中不同措辞的变化、框架效应或样本大小、其结果在多大程度上具有普遍性或者如何受到性别、阶级或文化等变量的影响。其主要的模棱两可之处在于,伦理思想实验的潜在读者究竟是一般人还是其他哲学家;同时,作为一个推论,它引出的判断究竟是专家的判断,还是普通人的判断。绝大多数的伦理思想实验实际上仍局限于学术期刊,并只在其他哲学家非正式的讨论中得到检验,也就是说,事实上,对它们的考察只限于那些对于伦理理论建构有专业认识的人,而不是更一般的代表性样本或者那些对思维实验旨在描述的现实环境上更有经验的人。


The problems of external validity are even greater. The crucial question is: even assuming that a thought experiment has internal validity, what follows from the validity of judgments in the world of the thought experiment for other cases? If you agree that it would be permissible to pull the lever in the original trolley problem, causing five people to be saved and one to die, there are a variety of inferences that could follow. At the most confined, we could take it that the result has implications only for cases involving runaway trains with particular switching arrangements. At the other end of the spectrum, we could take the result to have far-reaching implications about the permissibility of causing harm to some in the course of preventing harm to greater numbers of others. 

而外部有效性的问题就更大了:即便我们假设思想实验是具备内部有效性的,但思想实验构想的世界中所做的判断,应用在其他情况,有多有效呢?这又是一个关键的问题。在电车问题中,如果你同意拉动杠杆,让五人获救但一个人去死,这个结果可以有很多的推论。在最局限的情况下,我们可以认为这个结果仅适用于有特定的机关的有轨电车的情况下;在最开放的情况下,我们可以把结果推广为为了避免数量较多的人群受到伤害,可以伤害数量较少的人群。


Judges within the common law tradition face a structurally similar question when making a judgment. They need to supply reasoning to support their decision, parts of which can be filleted out as the ratio decidendi (reason for the decision) by future judges. The ratio gives the judge’s best approximation to the breadth of the precedent the case sets.

在普通法的传统中,法官在做判决时,面临一个结构上类似的问题,他们需要提供推理来支持他们的决定。未来的法官在参照先例时,就可以解析推理中的判决理由(ratio decidendi),他们根据判决理由,就可以为先例所能应用的广泛程度做出一个最佳的估量。


The broader the precedents that thought experiments can set, the more powerful they will be for ethical thinking. In turn, the breadth of the precedents that a thought experiment sets depends on the degree to which the controls in place in the thought experiment, which allow the particular hypothesis to be tested cleanly, imply or are compatible with the wider cogency of the resultant ethical principle. This is not straightforward, and is itself a frequent topic for contestation.

思想实验所建立的先例越广泛,它们在伦理思考方面就会越有价值。而思想实验中的控制手段的恰当程度决定了思想实验建立先例的广泛程度,恰当的控制手段应当能让我们清楚地测试出假设条件,从而暗示拟引出的伦理原则,或者让拟引出的伦理原则更有说服力。思想实验不应是直截了当的告诉你,而且他本身应当是一个经常引人讨论的话题。


The deeper question about external validity is whether thought experiments give insights into a single fixed picture that can gradually be reconstructed, or whether even well-designed thought experiments inform something more fragmentary, changeable and plural. Societies differ greatly in features such as wealth, inequality, population size, ethnic, linguistic and religious diversity, technological advancement, economic structure, ease of communication and travel, and the ability to collect taxes and maintain order without violence. Moreover, societies are continually shifting in terms of these structural variables, and sometimes rapidly, for example through processes of industrialisation or transition away from communism. The COVID-19 outbreak has vividly displayed the ways in which social norms and structures are more malleable than we assume. It is implausible to think that the actual optimal policy prescriptions would be the same, regardless of the societal context. 

关于外部有效性有更深刻的问题:从思想实验洞察出的固定设想能否逐渐改造?平衡的精心设计的思想实验能否揭示出零碎、多边、多元的东西出来?因为在财富、不平等、人口规模、种族、语言、宗教多样性、技术进步、经济结构、通讯和旅行的便利性、能否在无需暴力的情况下收税和维持持续的能力等等特征不同的情况下,社会是不同的。而且,在这些结构性的变量上,社会也在不断的改变,比如工业化和资本主义的普及,有时变化是很迅速的。比如,今年新冠肺炎疫情的爆发就就生动的给我们展示了社会规范和结构的可塑性,这超过了我们的想象。如果说在脱离社会背景下,还是给出一样的最优策略处方,那是无法让人信服的。


Many philosophers nonetheless wish to say that the correct ethical principles are unchanging. However, even if this were true, I suspect the principles wouldn’t be specific enough to provide useful advice, and the real work of ethical thinking would be in interpreting or specifying these principles. Compare a case where you go to someone for advice, and it transpires that you got exactly the same advice as everyone else, regardless of the specifics of your position. 

即便如此,很多哲学家坚持正确的伦理原则是不会改变的。但是,就算是真有这样的伦理原则,这些原则也会因为太宽泛,而无法给出具体的建议。由此,伦理思考又变成了如何去解释和细化这些原则。试想一下,你去向某人求助,他不管你具体是什么情况,会直接给你一个提供给所有人的一模一样的建议。


An alternate view of thought experiments would downplay their relationship to scientific experiments, and acknowledge that they are, as Daniel Dennett put it, ‘intuition pumps’: tools for persuasion via imaginative consideration of possibilities. Thinking of thought experiments as persuasive fictions wouldn’t obviate the problem of external validity, but might allow us to reframe it.

关于思想实验,另一个观点是淡化它们与科学实验的关系,例如丹尼尔·丹尼特(Daniel Dennett)所说:它们是“直觉泵”:它们是通过对可能性进行富有想象力的思考,来说服人的工具。把思想实验当成具有说服力的虚构故事,并不能避免外部有效性的问题,但这可以让我们重新构建它。


The idea that fictions can provide ethical insights seems correct; but it doesn’t follow that they do so reliably or in a way that allows ethical insights to be easily transported from one context to another. One important question is what the relationship is between a well-told story and one that is true, or ethically insightful. How things are presented in fiction is often simplified and distorted

小说可以提供伦理洞见的观点似乎是正确的;但这并不意味着提供的洞见是可靠的,或者是可以适用于其他情况下的。一个讲的好的故事和一个真实的或有道德洞察力的故事往往是有区别的。虚构的故事中所呈现的往往是简化的和扭曲的。


Using fiction as a means for ethical reflection – whether in thought experiments or in novels – will tend to raise the same questions of experience, abstraction and ‘too much knowledge’ that we considered earlier in discussing Thomson’s violinist.

不管是用在思想实验中,还是放在小说中,把虚构故事来作为道德反思的方法也会引发起专业人士对经验、概念的思考,这个“太多知识”的问题,上文中讨论托马斯的小提琴家的问题时我们已经提到了。


In some ways, this criticism is as old as philosophical reflection on art. In his Republic, Plato complained that poets knew nothing about the things they wrote about, whether war or shoemaking, but presented images that others equally as ignorant would find convincing. 

和对虚构故事引发伦理思考的批评同样古老的是,对艺术能引发哲学思考的批评。柏拉图在《理想国》中抱怨说:不管是战争还是制鞋,诗人对他们所写的东西一无所知。但对于和他们同样无知的人来说,诗人所呈现的就是具有说服力的。


Overall, ethical thought experiments are, at best, fallible ways of constructing simplified models that map rather imperfectly onto the world as we experience it, and can distort as much as they illuminate. So should we give up on them as sources of ethical insight?

总体而言,伦理思维实验充其量不过是构建简化模型的一种容易出错的方式。这些简化模型并不能完美的映射我们所经历的世界,它对现实的扭曲可能和它能阐明的道理一样多。所以我们应该放弃伦理思维实验作为道德洞察力的来源吗?


Responsible thinking requires calibrating our levels of credence to the reliability of our intellectual tools. Clearly, ethical thought experiments are not particularly reliable tools. But that’s not to say that we have other, more reliable tools. Pre-theoretical ethical ‘common sense’ is subject to distortions brought by prejudice, power and many other factors, and the reason why we turn to philosophical ethics in the first place is that it’s unclear how to resolve competing ethical duties that arise at a pretheoretical level. Ethical thinking is hard, and even our best tools for doing it are not very good. Humility should be the watchword.

对于我们的思考工具而言,我们需要根据它的可靠性来调整我们对他的信任水平。这才是负责任的思考。显然,伦理思维实验并不是特别可靠的工具。但这并不是说我们就有其他更可靠的工具。在构建理论性的伦理思考以前,人们的“常识”容易受到偏见、权力以及其他很多因素影响而扭曲。为了解决那时具有争议的伦理责任,我们致力于采用哲学伦理,这是我们的初衷。伦理思考是困难的,即使是我们最好的工具也不够优秀。所以我们应把谦虚当成格言。



  • 本文原载于 Aeon

  • 原文链接https://aeon.co/essays/what-is-the-problem-with-ethical-trolley-problems


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