(B)Albert Einstein famously said: “Imagination is more important than knowledge.” They’re both important,says physicist and Nobel Prize recipient Frank Wilczek, but knowledge without imagination is __51__. Take hissubject of theoretical physics. As Wilczek says a lot of what you do is to try to understand Mother Nature’s mindand her sense of beauty to see how the laws of physics could be more beautiful. 

    Not many people truly appreciate what happened in physics in the last part of the 20th Century. Weunderstood at a level whose __52__ would be difficult to exaggerate what matter is. We really have the equationsfor the different fundamental building blocks of matter – the different particles have mathematical __53__ that areprecise and elegant. They have no secrets; in principle we have the equations. 

    The bad news, however, is that we are not so good at solving them. There are still gaps in fundamentalunderstanding. We have very good equations or practical purposes, but they are kind of __54__; they are beautifulbut not quite as beautiful as they should be given that they are close to God’s last word in some sense. We’retrying to think of better ways to solve the equations, __55__ takes a lot of imagination because they describe anunfamiliar world – it’s a very small world and things behave differently in it. The only way to get experience is toplay around with the equations and imagine __56__ they might behave in different circumstances; it’s more likeimaginative play than anything else. 

     The laws we have discovered, especially in the quantum world, are so strange that you have to play withthem in your mind. Usually __57__ you imagine is wrong, but its mind expanding and every once in a while yousee something that may be right. Sometimes it even is right. 

    The questions we are now able to ask are so __58__, so extraordinary. What is most of the Universe made of?Are the laws of physics ultimately unified? What was the Big Bang like? You just say them and they have such__59__. The more you learn about the equations, the more you learn about physics, the more you learn howbeautiful it is. That’s the real value; it’s a(n) __60__ to the human mind.