A Lunchtime Conversation – Causality
Yesterday, over lunch, I was trying to explain in simple terms the idea of causality to a colleague of mine, and found that it is very difficult to wrap your head around, especially for the uninitiated. He had seen a documentary on The Big Bang (not the comedy show), and was trying to grapple with ideas around the age of the universe, parallel universes, and how, if there are infinite possible parallel universes, everything that is happening can, and will, happen over and over in slightly different ways for eternity, somewhere in the “multiverse”. Not exactly an easy concept to understand. I don’t fully understand it, but have thought about it at length, and have read many books and articles on the subject, from science fiction to actual science. The implications of the idea of “macro-causality” are staggering to the way we perceive the world around us, and our very being itself. I say “macro-causality” because this is the level that we observe interactions on a daily basis, without the use of a Large Hadron Collider, or even a microscope.
I went about by first using the idea of simple cause and effect; you drop a glass, gravity takes hold, glass hits ground, glass smashes. Ignoring all the physics of the shattering of the glass, and the way the shards are created by miniscule weaknesses in the glass’ structure, this is a concept any person can grasp. one thing leads to another.
I then continued by explaining the idea of “initial states”, and how the objects or interactions we choose to measure are dependent upon the initial state of the universe at the point we begin measuring. This state is usually arbitrary, but we cannot predict accurately unless we know what the starting point is. For instance, if I place my iPhone on the table lengthways, and someone accidentally drops a fork, the edge of the fork hitting the screen ans shattering it, the outcome is very different than if I had placed it at a 90 degree angle, perpendicular, and the falling fork missing the phone altogether. We could predict, from these two sets of initial what the outcome would be in wither case, but without knowing these conditions, our predictions would become mere guesses.
This is horrible simplified I know, but remember I was trying to explain this to a colleague who had only stepped into the rabbithole recently, and was trying to not overwhelm him straight away.
I went on to talk about causality, and how everything depends upon a previous state for it to be how it is now. For us to predict anything, the best way to do this is to have as much data as possible. For scientists to predict anything, they need to first take many things as a given, such as our understanding of physics, and what this means for physical interactions on any level. Once we have worked out what this initial state is, we can then see where things may go, how objects may interact, and what the outcome of any situation may be. Depending upon what level of accuracy you want to predict, the level of investigation into initial states will vary.
Now jump ahead with me, to the way we perceive our world, and our simple understanding of causality in our daily lives. You are driving your car to work one day, and depending on the conditions, one of several things may happen. Look at these scenarios, all based on the same idea, and see how the conditions will change the outcome.
2. The road is dry, so the car handles reliably. The car in front again stops suddenly. Your tyres grip the road and you come to a screaming halt without damaging the either car.
3. The road is dry, and it is still dark. The car in front stops suddenly, but its brake-lights fail to engage. Your car ploughs into the back of the car in front at speed.
4. The road is dry, but you are changing the station on your radio when the car in front stops suddenly. You swerve to avoid the car at the last second, and narrowly miss the car, but end up half-way up the gutter on the side of the road. Pedestrians swear at you, and you are embarrassed by the situation.
In all these scenarios, imagine nobody was hurt, and the only damage is to the cars themselves. However, in all 4 scenarios, the take-away cafe latte in your drinks compartment topples over, leaving your car smelling of milk and coffee. There are many ways for any incident to unfold, but there is only one way in which it actually does, given that our perception of time is linear, and that each individual occurrence can only happen once at any given time along this linear timeline. Had we within our knowledge all of the conditions in this simple scenario beforehand, we could safely predict which of these scenarios would unfold with some level of accuracy. But the world around us is so complex, so multidimensional and multifaceted, that it seems to the feeble human brain that all things are random. There are so many variables that could potentially affect any given situation that we can’t possibly fathom this. If we could, however…
Do not confuse the above scenario with inevitability. All things that happen are somehow inevitable, because otherwise they wouldn’t happen. But even if we knew all the situations and conditions leading up to a potential outcome, would we then be able to change the future? Who knows?
The conversation then went back to its starting point, the idea of The Big Bang, and why this is important to physics, and what it means to our lives as human individuals. If scientists can know the initial conditions of the universe, they can then predict with some kind of accuracy what the ultimate fate of the universe is. Professor Lawrence Krauss discusses this idea in his book A Universe From nothing, and though 90% of this book was well over my head, it’s a convincing enough argument that I have to give it credence.
But why does the beginnings and endings of the universe matter to us? Because, simply, we are part of the universe. Contrary to public belief, humans are not creatures that inhabit a universe, we are actually part of the fabric of this universe. Our atoms are created within stars, as are all the atoms around us, which have temporarily settled in one place and time to be part of us, and what makes us up. So to understand the system within which we find ourselves, i.e. the universe, we are actually beginning to understand ourselves. As Professor Brian Cox once said:
Once we realise this, we can see the astounding and confusing universe around us in a much clearer light. And we can see that the initial state of the universe not only affects the universe at large, but is the reason for everything being how it is now.
The last part of our conversation was about how causality negates free will. If we are indeed living in a causal universe, one where the precedents of history create the present, and the present creates the future, we are at the whim of history. In order to get to where we now are, there needed to have been an exact series of events which lead up to it., and they must have happened in exactly the right sequence. While this may seem mundane, a small change in the initial state of the universe, when extrapolated over 14.3 billion years, would have immense consequences, the least of which being that humanity may never have evolved.
But this series of events also includes the goings on within our brains. So often we think of our minds working autonomously within the universe. Se see thought arise “spontaneously”, we are creative, we are inventive, and we are capable of many intangible things such as emotion and exaltation. We have a very strong sense of self, because we only ever perceive the universe from behind the veil of our own bodies, and through the way our minds interpret things. But our minds, like ourselves, operate within the universe, are part of the universe, and therefore are at the whim of the initial state of the universe for all thoughts and actions that arise within it. Everything we decide, everything we do, every thought and dream and aspiration, all are subsequent through 14.3 billion years to the initial state of the universe. Once you take this into consideration, our very notion of free will falls on its head.
And yet, in order to continue to operate, we must exist as if free will does exist. Our brains and our sense of self, our sense of purpose, our sense of meaning, and our understanding of the day to day reality, all operate in a way that “seems self determined”/ But this cannot be, not if the universe is a causal one.
This idea of causality is one that has religious folks scared, because one of the premises of the major religions is that of “free will”. As Sam Harris illustrates in his short book “Free Will“, albeit briefly, the idea of free will in a causal universe is nonexistent, to such an extent that even a murderer cannot be held responsible for his own actions. The event of a murder was set in motion by events in the past, all events in the past, leading up to that moment where the person “decides” to pull the trigger. In a religious sense, this is free will. Free will is the scapegoat for a religious belief that god has given us the choice to do what we do, and to either follow his divine plan, or forsake it. Therefore, the idea of a loving god can be held intact, as we watch all the people around us doing things we deem to be wrong, such as murder, and the fault then lies with the individual rather than being the victim of 14.3 billion years of circumstance. The understanding that free will does not exist tips all this on its head, and creates a problem for our judicial system which depends upon the “decisions” and actions of people for its ability to mete out punishment for offenders. This is an idea that is well worth pursuing, and one I may write about in future (if causality allows for it).
By this point in the conversation I could see my colleague’s eyes glazing over. Too much information, too quickly, and over a couple of beers, and the conversation was wearing on him. Besides which, we only had an hour for lunch, so it was time to go back to work.But even this conversation would never have happened, if the initial state of the universe were different. Just something to think about next time you’re pondering your existence.