Like many other people—over $820 million worth of people in the US alone,according tothe latest box office results I read while writing this post—I just sawGuardians of the Galaxy Vol. 2. It’s lots of fun—psychedelic colors, battles in space, and great ’70s music played on a Walkman.

它还表现出一个不开心的、不断膨胀的大脑伪装成一个星球，寻求统治世界。这是一个问题，一个非常大的问题，需要守护者去解决。在没有透露太多关于守卫者如何遭遇邪恶大脑的情节的情况下(这是一个相当单薄的情节;所有的乐趣都在行动中)，守卫者的问题是如何对抗大脑的狂妄自大。

In order to understand and ultimately defeat the evil of the brain, the guardians need to figure out what’s driving it. There’s a famous philosophical thought experiment about a brain in a vat that might help them. The thought experiment, originally proposed by Hilary Putnam, is rooted in Cartesian skepticism: how do you know all your experiences aren’t illusory? One version goes like this. Imagine the possibility that you are a brain in a vat, artificially maintained and stimulated, just a brain, floating there. Wouldn’t it still be possible for you to have all the experiences, memories, thoughts, or emotions that you are now having? So, how do you know you aren’t a brain in a vat?

Putnam’s answer to this, called “semantic externalism,” was that your thoughts can’t be thoughtsofsomething unless they refertosomething that actually exists. Your thoughts might be thoughts of something else—vat-trees—but they aren’t thoughts of trees. For you to have thoughts of what we mean by trees, there must be real trees.

现在想想爱。缸中的大脑会恋爱吗?或者大脑所经历的情感仅仅是大脑对物体的爱吗?(如果你的伴侣只是你想象中的虚构人物，你还会爱他吗?)假设大脑意识到了这一点——它感受到的爱可能只是一个大大脑物体的爱，而不是一个真实的物体?这是一个怀疑论的观点，毕竟大脑喜欢的对象只是一个大脑对象，大脑不能确定两者的区别。

How might the vat-brain respond, if this recognition made it feel lonely or sad? Might it want to try to make a real object for its love? And if it realized that the object it had made was only a vat-object, not a real object, what then? How would the vat-brain react if it came to the realization that what it thought was reciprocation of its love was only vat-thinking-reciprocal-vat object? Might it get mad and terminate the vat-object for not being real? Kill off the vat-object, to try again? Might it then make another vat-object, and another, and another, each time coming to the realization that it was destined to be frustrated in love because vat-brain-love of a vat-object isn’t real love of something real?

更糟糕的是，想想权力。假设缸中的大脑需要能量。如果没有什么东西可以让它控制，它还能有力量吗?(没有东西可以霸占，你还能强大吗?)假设大脑壶意识到，为了使其权力行使的经验成为真正的权力行使，必须有外部对象让它有权力支配?在怀疑的指控上，它不能知道是否存在这样的对象，所以它不能确定它所认为的权力的行使是否只是一种幻觉。那么它会做什么呢?它可以尝试创造具有权力的东西，但同样的问题是，它们可能只是一些空洞的东西，而不是真正的东西。因此，就像对大缸对象的爱一样，对大缸对象的权力似乎是空的。至少，大脑壳无法判断它所认为的权力行使是否仅仅是一种幻觉。

Confronted with these despairing conclusions, what might a vat-brain do? Make itself so big that there’s no room for anything else in this and every other galaxy? Maybe the next best thing to exercising power over external objects would be to deny their very possibility, swallowing up the whole world and in so doing extinguishing any possibility other than the pure exercise of power.

Is this what the vat-brain thought experiment might ultimately become: the megalomania of the vat-brain? A world in which the vat-brain can be sure vat-brain is all there is, rather than a world in which the vat-brain worries about whether it can ever reach out beyond itself? Such megalomania is the frightening prospect faced by the galaxy’s guardians.

这些思想实验不仅仅是无聊的好奇心。他们让你思考激进的怀疑论会把你引向何方。它会让你变得狂妄自大吗?如果你不知道你是世界上的一个存在，在与世界上的真实事物的真实关系中，也许你就是世界，整个世界，你可以用它做任何你想做的事。也许这就是你的全部——最终你会意识到，你所关心的只是你自己和你纯粹的霸权。

But if you think this way, and you are wrong and we really do exist outside of you, we just might need some guardians to protect ourselves against you….