It occurs to me today that if time travel is possible, not only will the chain of causes and effects be disrupted, but also the law of mass conservation will be broken. Science fictions seem to like exploring the consequences of the former, a few of which I happened to watch this week, such as Back to the Future and Star Trek. In those movies, things called parallel universes or alternative realities come to rescue the logical sequence of causes and effects. But I haven’t seen anyone trying to explain what happens to the broken law of mass conservation. Einstein might have a solution: instead of the conservation of mass, it is the conservation of energy. But energy is a slippery concept that anything can turn into a form of it or transform from one form into another .

Now jump to a totally unrelated perspective. During a dialogue between Buddhist monks and theoretical physicists, the monks likened the meditation in Buddhism with maths in physics. Maths in physics is a tool to guide the logic reasoning; and through years of experience, users of these maths tools can see through the symbols and equations and get direct intuitions of the actual physical images and relationships they represent.  For example, Jonh Pendry, the theoretician who proposed the construction of negative-refractive-index meta-materials, said the idea of split-ring resonators came to him on a raining afternoon when he was playing around with Maxwell equations. Similar things happen in meditation, the monks said: only through years of practicing meditation, they start to see things normal people don’t see (figuratively, and maybe literally as well).

This argument strikes me particularly strong because science thrives due to human intuition, and if there is another completely different source of intuition that hasn’t been explored, it means that we have left many things out of our considerations, and hence whatever we come up with in science to explain the world is incomplete.

When teaching young Luke Skywalker the art of Jedi, Yoda famously said “You need to unlearn what you have learned” in order to learn how to use force, for example to levitate a spacecraft. So it seems that to leave a slight doubt on everything, including what we believe and what we hold as absolute truth, is necessary for a healthy science.

But it’s not just about science. Humans are known for mistaking beliefs with facts, and convictions with truth. To acknowledge the one is fallible and to accept that fact is essential in any relationship not only between us and the physical world, but also among ourselves, humans. And as colleagues, we have ups-and-downs in our relationships in the past year, and will definitely have more ups-and-downs in the coming year. I treasure all those experiences, and am thankful for everything we have shared in the past year, and look forward to the exciting things coming in the new year.

Now what do all these have anything to do with holidays? Wait.

So if the law of energy conservation doesn’t hold, what disrupt it? It is the FORCE! (Recall the derivatives of energy with respect to distance is force!)

On the occasion of a new decade, I wish all of you “MAY THE FORCE BE WITH YOU! “.

Warm regards,
Wendong

PS. This is my new year’s greeting letter to my group. Weird chain of thoughts.

Cartoon Source: http://athene.as.arizona.edu/~lclose/teaching/nats102/time_travel_cartoon_2.gif