At some point in our life, we come to accept the fact we are closer to death than life. What lies ahead is definitely less significant than what is left behind. These are the twilight years, and I have come to accept them. With darkness descending over the horizons, and the long shadows of misspent years and evaded human conditions slithering all around me, I peer into the void, into an eternity of silence and dreamlessness. It is almost time.
Since the post series on Particles and Interactions became a bit longer than I wanted, I thought I would break it up. Let’s start with a recap of modern physics that will you will need to understand the structure of matter.
When we looked at Quantum Mechanics, we talked about its various interpretations. The reason we have such interpretations, I said, is that QM deals with a reality that we have no access to, through our sensory and perceptual apparatuses. On the other hand, Special Relativity is about macro objects in motion, and we have no problem imagining such things. So why would we need to have an interpretation? The answer is a subtle one.
Whenever we talk about Quantum Mechanics, one of the first questions would be, “What about the cat?” This question, really, is about the interpretations of Quantum Mechanics. The standard interpretation, the so-called Copenhagen interpretation, leads to the famous Schrodinger’s cat.
In this post on Quantum Mechanics (QM), we will go a bit beyond it and touch upon Quantum Field Theory – the way it is used in particle physics. In the last couple of posts, I outlined a philosophical introduction to QM, as well as its historical origin – how it came about as an ad-hoc explanation of the blackbody radiation, and a brilliant description of the photoelectric effect.
Quantum Mechanics (QM) is the physics of small things. How do they behave and how do they interact with each other? Conspicuously absent from this framework of QM is why. Why small things do what they do is a question QM leaves alone. And, if you are to make any headway into this subject, your best bet is to curb your urge to ask why. Nature is what she is. Our job is to understand the rules by which she plays the game of reality, and do our best to make use of those rules to our advantage in experiments and technologies. Ours is not to reason why. Really.
In all our scientific endeavors, we use similar high-level techniques to understand and study things. The most common technique is reductionism. It is based on the belief that the behavior, properties and structure of large and complex objects can be understood in terms of their simpler constituents. In other words, we try to understand the whole (the universe, for instance) in terms of smaller, reduced constituents (such as particles).
Animals have different sensory capabilities compared to us humans. Cats, for instance, can hear up to 60kHz, while the highest note we have ever heard was about 20kHz. Apparently, we could hear that high a note only in our childhood. So, if we are trying to pull a fast one on a cat with the best hifi multi-channel, Dolby-whatever recording of a mouse, we will fail pathetically. It won’t be fooled because it lives in a different sensory world, while sharing the same physical world as ours. There is a humongous difference between the sensory and physical worlds.
Free will is a problem. If all of us are physical machines, obeying laws of physics, then all our movements and mental states are caused by events that took place earlier. What is caused is fully determined by the cause. So whatever we do now and in the next minute is all pre-ordained by antecedent events and causes, and we have no control over it. How can we then have free will? The fact that I am writing this note on free will — is it totally and completely determined by the events from time immemorial? That doesn’t sound right.