The leaves are starting to change in our neck of the woods. We have a sweetgum tree in our front yard with a delightful mix of green and yellow leaves throughout. It’s beautiful, and I’m starting to see that part of the beauty is in the randomness of it. There is no visible rhyme or reason for which leaves are yellow and which are still green. It seems to me randomness is a huge source of the beauty that we find in the world.

Scientifically speaking, quantum mechanics is the source of much of the randomness that we perceive in the world. It is therefore a source of much of the beauty that we see.

In this final post on the mysteries of quantum mechanics I want to talk about Schrodinger’s Cat. Edwin Schrodinger was one of the forefathers of quantum physics. I don’t know if he actually had a cat, but there is a famous thought experiment that is centered around such a pet. Here it goes.

Imagine if we put a cat in a box with a vial of poison that is released when a radioactive element decays. We close the box and have no way of observing what is happening inside. Radioactive decay is a quantum event and we can calculate the probability of it happening in a given amount of time, but we can’t calculate exactly when it happens. So as time passes, the likelihood of the radioactive element decaying and releasing the poison increases and with it the probability that the cat is dead goes up. But without observing the contents of the box there is no way for us to know what the state of the cat is: alive or dead. The language there is important. To our minds, it is an either/or: The cat is either alive or it is dead. But quantum mechanics resists such precision. Cause and effect is fuzzy in the quantum world. Quantum mechanics describes reality using ‘and’ rather than ‘or’. Meaning that according to quantum mechanics the cat is both alive and dead. It is both/and. It’s a bit like how an electron can be both a wave and a particle (see last week’s post).

Obviously when the experimenter opens the box, they will either find a dead cat or a living cat. They won’t find a cat stuck in some creepy state between alive and dead. But that is part of the mystery of quantum mechanics, because the state of the cat is neither of those options while the box is closed. It is only when the box is opened and the cat observed that the ‘both/and’ reality becomes and ‘either/or.’ You could almost say that opening the box and observing the cat forces it to choose between the options of dead or alive.

This is the way that quantum mechanics describes our world and so far over a century of experiments have confirmed the accuracy of this view.

There are so many strands to this mystery that we could pick up. One that strikes me as particularly amazing is the way that time and cause-and-effect must function in the quantum world. For example, if we opened the box and found that the cat was dead, quantum mechanics says that it became dead when we observed it. Before that it was both dead and alive. If observing it ‘forced’ it to die, then that means that our observation also forced the radioactive decay that released the poison to have happened in the past. Before we looked there was a probability that it had occurred, but observing it made the occurrence a reality. Which basically reverses our standard way of thinking about cause-and-effect. Our later action of opening the box, seems to have caused the previous action of the radioactive decay.

If this doesn’t make sense to you, then you’re in good company. It doesn’t make a lot of sense to anybody. For over one-hundred years, the smartest scientists and philosophers have tried to make sense of what this all means. But no one has figured it out yet. Importantly though, the theory works. Our smart phones depend on quantum theory to function. This is not just obscure science that doesn’t interact with our daily life. Quantum mechanics is embedded in our modern technological age. We can utilize it, even if we can’t understand it.

I am reminded through this that there is deep mystery alive in our world. And should we expect anything less? The God who created this universe is infinitely greater, infinitely more mysterious than we will ever know. Studying His creation leads us to more knowledge, but also into greater awe and wonder as we are faced with paradoxes and mysteries beyond our comprehension. There is great mystery even in the changing of the leaves during the autumn months. There is randomness at the heart of much of what we observe. Or at least it seems random to us.

I don’t think this is accidental. God is wooing us. God has filled His creation with things that point us beyond the creation and towards Himself. He is the mysterium tremendum, the awe-inspiring mystery, and his creation reveals this to us. We get glimpses of his beauty and mystery even through a deep study of physics. I suspect it is the same for all the natural sciences. For they all seek to understand a world that points past itself toward its infinitely mysterious Creator.