我车库里的龙

“一条会喷火的龙住在我的车库里。”

假设我一板正经地对你说出这句话，我相信你一定会想亲自去看一眼。有关于龙的故事流传了成百上千年，但是从来都没有证据证明其存在，正所谓机不可失时不再来。

“让我看看”你说道。我把你领进我的车库里，你看到里面有架梯子，空的涂料桶，还有一辆旧到掉渣的三轮车，但是就是没有龙。

“龙在哪？”你问。

“她就在这呢，”我会回答道，大概指了指前面，“我忘了告诉你，她是条会隐形的龙。”

你建议在地上撒上些面粉，那么我们就可看到龙的脚印了。

“建议是不错，”我说：“但是这条龙浮在空中。”

然后你建议用红外线传感器探测看不见的火焰。

“建议不错，”我说：“但是这个火焰同时是没有温度的。”

你打算用喷漆让龙现形。

“建议不错，”我说：“但是她是条非物质的，无形的龙，漆不会留在她身上的。”就这样一直下去，你所有物理探测的建议我都能用一个特别的解释反驳你，告诉你为什么你的建议行不通。

那么现在一只隐形、无形、浮在空中、能吐无温火焰的龙和根本就没有龙的区别究竟在哪里呢？如果没有办法驳斥我的论点，没有可以想象的实验来证明，那么说我的龙存在有什么意义呢？你没有能力去推翻我的假设并不代表这个假设是真实有效的。不管一个主张有多么令人振奋，多么让人惊奇，如果无法测试、无法推翻它，那么这个主张在实际上则一点意义都没有。我需要你做仅仅是去信其有，在没有证据的情况下，在我的一家之言的基础上。在我的执意之下你唯一真正了解到的东西会是觉得我脑子有些不太正常。你也许会想，如果没有物理测验，究竟是什么说服了我？你会觉得也许是幻觉或者是梦境的原因。但是即使这样，我为什么要这么一板正经地说呢？也许我需要帮助吧？至少我低估了人类的不可靠性。想象一下，尽管没有一个实验结果是成功的，但是你特别特别想接收新的思维，新的视点，所以你不立刻反对在我车库里有着条会喷火的龙的想法。你仅仅把这个想法放到一边，尽管现有的证据是非常反对这个想法的，但是如果有新的数据出现了，你便会立刻准备去检查这段数据，看看是否能说服你。当然我对你大发脾气仅仅因为你不信我，说她未被证明，或者批评你古板并且缺乏想象力对你来说是相当不公的一件事。

再想象一下，故事的发展出现了不同的走向。龙是隐身的，但是在你的观察下脚印在铺满面粉的地面上出现了。你的红外线传感器爆了表。喷漆后在你面前突然显出来一块锋利的鬃毛。不管你之前有多么怀疑这条龙的存在，隐形这条线不说了，你现在不得不承认那里有个什么东西，并且看上去同一条会喷火的隐形龙的描述高度吻合。

再换一个场景：假设不仅仅是我，假设你许多的朋友，你确定他们互相不认识，都告诉你在他们家的车库里住着条龙，但是每家的龙都有着同样含糊不清的证明。我们所有人承认我们都非常不解我们为什么都会有如此奇怪的，毫无物理依据支撑的信仰。我们都没有疯。我们猜测如果世界到处都有隐形的龙藏在车库里会是什么样子，而我们才刚刚了解这件事。我当然不希望这一切都是真的，说实在的，但是也许那些欧洲以及中国关于龙的神话并不仅仅是神话而已。

令人高兴的是，有些龙级的大脚印出现在了地板上。但是从来都没有在怀疑论者（原文skeptic）观察的的时候出现。这个时候又有其他的解释出现了。在仔细观察下那些脚印似乎是假的。另一个“巨龙粉丝”出现声称他的手指被龙的烈焰气息所灼伤。但是同时，别的可能性也有存在。众所周知，把手指灼伤的方法并不止龙的烈焰气息。这些所谓的“证据”，不管“巨龙粉丝”认为有多么重要，还远远不足以令人信服。再一次，唯一的讲得通的方法便是试探性地否定龙[存在]的假说，带着开放的心态面对新的物理数据，并且同时思考是什么能让如此多的看起来精神正常、头脑清醒的人们共享同样的奇异幻像。

“A fire-breathing dragon lives in my garage”

Suppose (I’m following a group therapy approach by the psychologist Richard Franklin) I seriously make such an assertion to you. Surely you’d want to check it out, see for yourself. There have been innumerable stories of dragons over the centuries, but no real evidence. What an opportunity!

“Show me,” you say. I lead you to my garage. You look inside and see a ladder, empty paint cans, an old tricycle — but no dragon.

“Where’s the dragon?” you ask.

“Oh, she’s right here,” I reply, waving vaguely. “I neglected to mention that she’s an invisible dragon.”

You propose spreading flour on the floor of the garage to capture the dragon’s footprints. “Good idea,” I say, “but this dragon floats in the air.”

Then you’ll use an infrared sensor to detect the invisible fire.

“Good idea, but the invisible fire is also heatless.”

You’ll spray-paint the dragon and make her visible.

“Good idea, but she’s an incorporeal dragon and the paint won’t stick.” And so on. I counter every physical test you propose with a special explanation of why it won’t work.

Now, what’s the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all? If there’s no way to disprove my contention, no conceivable experiment that would count against it, what does it mean to say that my dragon exists? Your inability to invalidate my hypothesis is not at all the same thing as proving it true. Claims that cannot be tested, assertions immune to disproof are veridically worthless, whatever value they may have in inspiring us or in exciting our sense of wonder. What I’m asking you to do comes down to believing, in the absence of evidence, on my say-so. The only thing you’ve really learned from my insistence that there’s a dragon in my garage is that something funny is going on inside my head. You’d wonder, if no physical tests apply, what convinced me. The possibility that it was a dream or a hallucination would certainly enter your mind. But then, why am I taking it so seriously? Maybe I need help. At the least, maybe I’ve seriously underestimated human fallibility. Imagine that, despite none of the tests being successful, you wish to be scrupulously open-minded. So you don’t outright reject the notion that there’s a fire-breathing dragon in my garage. You merely put it on hold. Present evidence is strongly against it, but if a new body of data emerge you’re prepared to examine it and see if it convinces you. Surely it’s unfair of me to be offended at not being believed; or to criticize you for being stodgy and unimaginative — merely because you rendered the Scottish verdict of “not proved.”

Imagine that things had gone otherwise. The dragon is invisible, all right, but footprints are being made in the flour as you watch. Your infrared detector reads off-scale. The spray paint reveals a jagged crest bobbing in the air before you. No matter how skeptical you might have been about the existence of dragons — to say nothing about invisible ones — you must now acknowledge that there’s something here, and that in a preliminary way it’s consistent with an invisible, fire-breathing dragon.

Now another scenario: Suppose it’s not just me. Suppose that several people of your acquaintance, including people who you’re pretty sure don’t know each other, all tell you that they have dragons in their garages — but in every case the evidence is maddeningly elusive. All of us admit we’re disturbed at being gripped by so odd a conviction so ill-supported by the physical evidence. None of us is a lunatic. We speculate about what it would mean if invisible dragons were really hiding out in garages all over the world, with us humans just catching on. I’d rather it not be true, I tell you. But maybe all those ancient European and Chinese myths about dragons weren’t myths at all.

Gratifyingly, some dragon-size footprints in the flour are now reported. But they’re never made when a skeptic is looking. An alternative explanation presents itself. On close examination it seems clear that the footprints could have been faked. Another dragon enthusiast shows up with a burnt finger and attributes it to a rare physical manifestation of the dragon’s fiery breath. But again, other possibilities exist. We understand that there are other ways to burn fingers besides the breath of invisible dragons. Such “evidence” — no matter how important the dragon advocates consider it — is far from compelling. Once again, the only sensible approach is tentatively to reject the dragon hypothesis, to be open to future physical data, and to wonder what the cause might be that so many apparently sane and sober people share the same strange delusion.