Stephen himself is a wonderful example of sophisticated, yet practical, illusion. It seems that he is confined to his wheelchair, incapable of moving anything but his right eye. But I believe he travels and moves about with more brilliance and curiosity than any other living person. I believe he leaves his body and soars in exploration of the cosmos, returning with reports of black holes and otherworldly civilizations.

I know him because for a time we had the same publisher. We met at parties and formed a friendship. When he'd come to America, I'd host parties for him, inviting people who weren't exactly part of my usual crowd, but I loved meeting them.

He has two pictures over his desk at Cambridge University: one of Marilyn Monroe and one of Albert Einstein. He told me (through his electronic chair) that "the curves of the universe are as beautiful as Miss Monroe." He also told me, and he has said so publicly, that he is certain he is the reincarnation of Sir Isaac Newton. He was born exactly three hundred years after Sir Isaac died, and he holds the Newton Chair at Cambridge.

Stephen Hawking is both a grand and a simple man. His intellect is without bounds, but it's his humor and wit that attract me. When he was more agile, I used to watch him gleefully maneuver his "golden" wheelchair around the streets of Cambridge, defying anyone to get in his way. The word spread quickly around the campus that Stephen was on the loose again—Be alert!

When I was in the United Kingdom shooting Downton Abbey in 2012, I emailed him, and he invited me to lunch, but I received the invitation a day late. I was crestfallen. It made me ask myself whether the speed of a loving thought was faster than the speed of light (186,282.397 miles a second) and if I had missed his invitation because of it. I called him and, through his caretaker, asked him the question. He took a while before he answered via his chair. "The two are not comparable," he said, making me laugh by giving such a scientific answer to my more "philosophical" question.

Maybe the truth is that nothing is comparable to anything else, particularly if each of us is our own universe and we create everything around us. That probably sounds like New Age blather, I know. But what if it's true? I sit and talk with other people, confident in my belief that they are actually there, but what if they are only in my creative daytime dream, just as they might sometimes turn up in my dreams at night? Even more important—what if my night dreams are the expression of my internal yin (female) side, and the daytime dream reality is an expression of my more demonstrative external yang (male) side? What if each of us needs to respect the night and day illusions equally?

I would have to say the daytime (yang) masculine expression of "reality" is what has reduced the human race to the deterioration we are now experiencing, whereas the nighttime (yin) female reality might have afforded us the opportunity to search with more compassion and keener accuracy for who we are and what we really want. Of one thing I am certain: I create everyone and their behavior in my dreams at night. Why is it so hard to admit we are creating the same thing during the turmoil of our busy days?