We are 2-dimensional creatures in a plane. The truth (or the Forms, in Plato’s words) is a 3-dimensional maze which rests on that plane. We can never understand the 3-dimensional maze itself, but we can see the shadow of the maze projected onto the plane, which as well constructs a 2-dimensional maze. Viewing from different angles, there are many entrances to the shadow maze. We can choose any entrance we want to enter the shadow maze. Some of the entrances lead to ugly, complicated and winding routes while some lead to beautiful, simple and symmetric routes. Perhaps both kinds of the routes can eventually lead to the most intrinsic essence of the maze. Yet, we would without hesitation prefer the more comprehensible path. The simpler the route is, the further we are likely to reach and the more we are likely to see.
What is Physics for?
I once believed that physics is unique. God determines every law that governs nature, unknown but immortal. We keep pursuing the ultimate of the universe, whereby we could talk to God and try to understand the message God has left for us. Before, people believed in myths such as gods driving the Sun to orbit the Earth. We then abandoned geocentricism and adopted heliocentrism. Later, Newton discovered gravity and told us the laws of motion…… Science has greatly progressed. It seems that every time a new theory comes into light, we rectify some widely accepted misconceptions and make a step further on the right course that extends to God’s will.
However, why do we commonly accept that the Earth orbits the Sun, rather than the Sun orbits the Earth? One says it is because the heliocentric theory provides us with a powerful tool to predict the motion of all the planets in the solar system. The truth is that geocentricism isn’t less capable to offer such predictions. One says it is because the heliocentric theory is consistent with Newton’s mechanics, which describes motions under gravity in pure mathematical language. The truth is that if we choose a reference frame where the Earth is at rest, we can develop pure mathematics that describes geocentricism, although the mathematics is much more complicated. Actually, geocentricism can do everything that heliocentrism can do. Of course, one argues that we believe in heliocentrism because it is the more concise explanation of the phenomenon. But why do we pursue conciseness? Could we ever prove that conciseness is the better and the more natural way to understand the universe? If not, why are we so confident that heliocentrism is the one closer to the ultimate truth?
Things only get more upsetting when we consider modern physics. In the past, we were at least able to tell which theory appeared to be more concise, but because modern physics deals with things that are either too small or too large for us to imagine with common sense, we have to inevitably establish various counterintuitive theories that are hard to grasp. To explain the wave-particle duality and the behavior of measurement in quantum mechanics, we have proposed nearly a dozen explanations, all of which are reasonable but different. Due to their opaqueness, it is impossible to tell which is the most concise or the most natural way of understanding, so which theory should we believe in as the truth? Besides, the string theory, regarded as the most potential candidate for the Grand Unified Theory of Everything, has a reputation for being extraordinary symmetric and beautiful in its mathematical structure. That’s why most people tend to believe in it for they think such a perfectness could only be created by God. However, we do not know whether there are other theories as beautiful as, or even more beautiful than the string theory, and the answer is probably yes. Moreover, string theory cannot be verified or overthrown by any known experimental approaches, so it is indeed more metaphysical than physical, at least for now. In a word, the interpretations and the explanations of nature largely depend on human beings. Because phenomena in such scales are too abstract and intricate, we often establish different explanations for the same thing, and we are unable to tell which one is the most correct.
Even if the ultimate truth of the universe is unique, we could hardly uncover it and we even could not make sure whether we are on the right course. Therefore, we would never know where physics is leading us. In this sense, physics seems to be merely an art, through which physicists express themselves by coming up with new elegant theories. The study of modern physics is like a little boy asking what the sun is. A painter gives him a drawing of the sun. A composer plays a piece of music symbolizing the sun. A poet writes a poem about the sun. Eventually, the boy gets confused. These works of art are all so beautiful that he does not know which one he should rely on. Even with them in his hands, the boy can never reach the sun himself. These pieces of art are all self-expressions of their creators, rather than a successful attempt to approach the ultimate truth. It seems that physicists are only playing games with numbers, reassembling the puzzles in a way they believe to be the best. In light of this, physics seems to be aimless and meaningless. What is the purpose of physics then? Could we ever find out the truth if every explanation is only an artifact made by us?
It is believed that a best explanation is the one closest to the truth, but how do we define what best is? What are the benefits that heliocentrism can bring to us but geocentricism cannot? In fact, the key point is not which theory stands out to be more correct, but which theory has the potential to tell us more things. We love conciseness, not because it is a more natural and more correct explanation, but because conciseness is more conducive for us to go on our explorations. Both theories are equally right, to some extent, but the simpler theory enables us to calculate and comprehend things in a much faster and more effective way. The conciseness and beauty of the equations help us to develop a new system of intuition, through which we are able to perceive things with more powerful insights. It keeps shedding light on new areas that wait for our discoveries. That’s why we keep developing physics. We are pursuing the conciseness, the elegance, the symmetry, the balance, the conformity, in a word, the beauty of physics so as to find out more things and to build up more intuitions about the universe. Although all of our theories may not be the exact truth or the best interpretation of God’s will, they at least point out a new path for us to further proceed. The purpose of physics is to look for such an explanation that we could read more messages that God has left for us, and we could discover more and more hidden beauty in our life. How do we know whether we are on the right course? In short, the more intuitions the theory helps us develop, the further it could lead us; the more enlightening the theory is, the better it would be.
For the Love of Physics
This is the first time I’ve written a blog, a blog just for the love of physics.
It was roughly one and a half years ago, on a cozy winter day, with spotlessly white snowflakes fluttering all over the sky, that I began walking on the path to the wonderland of physics for the first time in my life. I can still remember the excitement and surprise I had, which flooded out of my astonished mind like a violent fountain, when I got the first glimpse of the amazing world of physics, as if it all happened yesterday. I was so surprised, shocked, amazed, even going crazy for the beauty of physics, that I jumped and rolled back and forth, screaming insanely just like an idiot for nights and days, even though I had just touched physics gently with my fingernail.
It is often said that an interest is the best teacher, though on the other hand, a great teacher shapes your interests. Thanks to the Wangyi opencourse platform, which has offered me a chance to have lectures from the greatest teachers in the greatest university, a seed of the basic understanding and the love of physics was planted deeply inside my heart. I encountered Professor Walter Lewin in MIT via the software, the best physics professor I’ve ever known, and was deeply impressed by his fascinating lectures of great humor, which pushed me towards the palace of physics. Because of him, I not only started to regard physics as my love, but moreover considered it the faith of my life as well.
Actually, some time earlier, I had once tried to write essays about my study of physics on the WeChat Subscription, but however it had taken me a great deal of time, due to the formality and length of an essay required on the subscription, so I had to change to write a blog to save time. However, an article as short as this can never express my love of physics entirely, so I will devote myself into enjoying physics and record the happiness down in the series of the blogs every day in the future, which consist of every step of mine reaching the ultimate beauty of physics.