这是一张2012年的老照片，但是前两天被翻出来了，又引起了一场争议。她在上楼梯还是下楼梯？
时代杂志网站昨天说，这很可能是那条白金蓝黑裙子的翻版。因为，这只猫已经引发了不小的争议。虽然，远不如那条裙子般激烈。
Imgur 的用户比较一致，说猫在下楼，Reddit 用户在讨论这猫时看起来分岐很大，两种意见互不相让。而一些Facebook 的用户以猫尾巴摇摆的方式为依据，认为是上楼.BBC的一档节目称答案取决于墙砖的布局方向。每日镜报则引述其他贴子的观点，认为猫在下楼。英国电讯报则干脆在新闻标题中将其称为“新裙子门” （The new dressgate）。
其实，这事好象没有裙子那么复杂，不用那么费劲。我觉着猫在上楼，理由是如果是在下楼，镜头是看不到楼上地面的。至于，你如果说这只猫是在逆行，那就这样做结论吧：如果这只猫不是在逆行，那么，她是在上楼。
当然，你也可以说所谓楼下的地面不是楼下的地面，而是楼上的墙面或者天花板。呵呵，那就难办了。需要另一番论证。
你说呢？
CNET 采访了一位远在英国的行为科学教授，请他给个结论。这个教授长篇大论，听起来都蛮有道理的。但就是没有结论。记者几次打断他，让他给结论。最后，他毫不意外地说，两种可能性都存在。
教授都这味道吗？呵呵，不过，这位教授把焦点放在图顶部的那块是天花板，还是地面上。说解决了这个问题就可以解决上与下的问题。这，谁不知道呢？
也许，只能等2012年首发这张图片的原作者来解释了。但是，他的解释又能让多少人信服呢？比如，那条病毒裙子的厂商说裙子真的是蓝黑的，但说了白说，许多人看到的还是白金的。“病毒”传播的魅力，就在这里。看来，我小看了这只猫，这只猫也是经典，至少行为学教授是这么说的。
谁在乎这只猫在上楼或者在下楼？但围绕着上下的争议，包括围绕着裙子的争议，的确发人深思。我们对于自己的了解，或者说，对于人性的了解，实在十分有限，更不用说猫了。上下的争议，让我们明白，真相看起来简单，其实何其复杂。真相的求索，看起来容易，其实千难万险。我们究竟应该信任自己，还是不信任自己？怀疑、质证，新闻记者血液里应该充盈的这种精神气，究竟会把事情弄得更清楚，还是把事情弄得更不清楚？反正，我是更不确定了。
顺便说一下，猫猫的游戏还没有结束，狗狗也来凑热闹了。它在上楼，还是下楼？又犯难了吧，呵呵。
It would need a true academic to sort this one out. Thankfully, Behavioral Science professor Nick Chater of the Warwick Business School in the UK has risen to the task.
He contacted me to explain: "We see in 3D, even though our eyes only receive 2D images. This seems puzzling, because it can be shown mathematically that there is an implied number of 3D scenes that will create the same 2D images. Most of the time, our brain is spectacularly good at solving this problem. It usually turns out that precisely one 3D interpretation is 'sensible' and all the others are bizarre, in one way or another."
I am surrounded by bizarre images all day. I think of them as mere normality. After all, I live in Northern California.
However Chater continued: "Our brain uses the most 'sensible' 3D interpretation; and mostly -- except when we are being subjected to cunning visual illusions -- this works just fine. But sometimes there are two equally plausible 3D interpretations of the same 2D image. Famous examples include the Necker cube (http://en.wikipedia.org/wiki/Necker_cube) and Rubin's face-vase illusion (http://en.wikipedia.org/wiki/Rubin_vase). Then, the brain flips between one interpretation and the other."
Professor, my brain is flipping. Tell me, is the cat going up or down the stairs?
Chater explained that the cat image has two possible interpretations because of "the amorphous gray square at the top of the picture." He suggests we focus on "the angle between the plane of the staircase and the surface represented by this gray patch."
He told me: "When we see the cat as coming downstairs, the gray square is interpreted as ceiling -- and this makes an acute, roughly 45 degree, angle with the staircase. But when we see the cat as going upstairs, the gray square is now interpreted as floor -- and this makes an obtuse, roughly 135 degree angle with the staircase."
So which is it, professor? Up or down?
"If we could only tell the 'slant' of the mysterious square patch in relation to the staircase, we would know if it was floor or ceiling, and so there would be no ambiguity. But the image cleverly leaves the gray square bereft of any clues. So we flip from one interpretation to the other," he said.
What do you mean: "If only"? After all this intellectual explanation, we still don't have an answer? Worse, we will never have an answer unless the creators of this dastardly picture come forward and admit their bent?
How will we now get through the weekend?
