网友问题：
“There is a story about an ancient Chinese philosopher， Zhuangzi. Zhuangzi dreamt of becoming a butterfly. And he wondered if he was a man who dreamt of being a butterfly or a butterfly that dreamt of being a man. Prof. Hawking， how do we know if we are living in our dreams or reality？”（中国古代有个哲学家叫庄子。‘昔者庄周梦为蝴蝶’，梦醒后，庄周不知是他梦为蝴蝶，还是蝴蝶梦为庄周。霍金教授，请问我们如何知道我们是生活在梦里还是真实存在？）
霍金回复原文：
Thank you for your question！ Zhuangzi dreamt of being a butterfly - perhaps because he was a man who loved freedom. I might dream of the universe and then wonder if the universe dreamt of me. To answer your question how do we know if we are living in our dreams or reality - well， we just don‘t and perhaps can’t！ At least not until we start to understand more about consciousness and the universe. We must keep striving for an understanding of the fundamental questions of existence. And then perhaps we will know whether the butterfly - and the universe - are real or just in our dreams. （中文翻译：谢谢你的问题，庄周梦蝶或许是个热爱自由的人，我也许也会梦到宇宙，然后困惑是否宇宙也梦到了我。来回答你的问题：“我们如何知道我们是生活在梦里还是真实存在？” —— 好吧，我们不知道，也许也无法知道！这个问题至少要等到我们开始深刻地了解意识和宇宙时才可知。我们必须要孜孜不倦地探索关于存在的基本命题，只有这样，我们也许才会知道蝴蝶（或宇宙）是真实存在，还是只存在于我们的梦里。）
