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Reality

So You Think There are Laws in Nature?

Eleni Angelou eavesdrops on a conversation between a Believer and a Sceptic.

Two friends are debating whether there are laws in nature. Bob is a ‘Believer’; he sees regularities everywhere, and supposes that some of them are good enough to be laws. Sue is a ‘Sceptic’; she feels that randomness prevails and the so-called ‘laws of nature’ are merely projections of our minds onto the world. Two worldviews oppose each other. Who will win?

Sue: Here we are, another Thursday, meeting up before a new movie starts. Who would have expected our friendship to last long enough to establish a movie habit together?

Bob: I know! Some things in life happen rather accidentally – like the meeting of two strangers who become involved enough to have their own little patterns in a relationship. Actually, I’ve been thinking about patterns and regularities a lot lately.

Sue: I’ll consider that another side-effect of studying philosophy. Do you want to share your thoughts while we’re waiting?

Bob: Sure. Well, look around you… Open a history book if you need to. Study some physics. Maybe even some economics. Observe your daily routines, or the routines of your roommate. There are patterns everywhere. If it weren’t for patterns, repeated behaviors, or regularities, life would be much more confusing and difficult, because it’d be even more unpredictable than it already is.

Sue: Wouldn’t that be interesting to see, though?

Bob: Maybe. That’s a good point. The sun rising in the west would be an inspiring trouble-maker, a paradigm-shifter, even. It would definitely provoke a new kind of inflammation on social media. But imagine all the things we’d mess up if the world weren’t predictable. No plans could be made, no promises would be kept. It would be hard to have our meeting this evening, or head to the movie later. Though that isn’t my point. I’m pretty sure that us watching a movie on Thursdays is not a law of any sort, even though it is a regularity. It’s certainly been a long time since we didn’t go to a premiere on a Thursday.

Illustration © Jaime Raposo 2021. To see more of his art, pease visit jaimeraposo.com

Sue: Sometimes once you start talking, it feels as if you might keep going on forever… But if I have to choose between your words and awkward silence, I think I’ll go for the words! At least this way I can challenge them!

Bob: I’m glad I can share my thoughts with you. My point though is that there are regularities everywhere you look. And that tells us something about how the world is. Of course, as I said, not all regularities are laws of nature. Imagine us having a stalker who observes us going to the movies every Thursday. After having seen us doing so for twenty-five Thursdays, he thinks, ‘‘I can now predict what those two are going to be doing this Thursday, and based on past evidence I’m pretty sure my prediction will be true, so I won’t follow them to the movies just this time.’’ Our stalker does some basic intuitive probability calculations, may think he knows us well, and doesn’t mind risking it for once. Having trusted his inductive inference, he believes that it is most likely we would go to the movies for the twenty-sixth time. However, he doesn’t think that we must go or that it’s necessary that we go. Contrarily, if it were a law of nature that we went to the movies every Thursday, it would happen necessarily ; nothing could prevent it. Yet, on that particular Thursday, your favorite band is in town and we decide to go to the concert instead.

Sue: First of all, why is seeing regularities everywhere telling us something about how the world is and not about how we are? I find that naïve, to say the least. It’s draining to have to keep objecting to people who make assumptions about how the world really is based on their narrow personal experience. Don’t you think that the appearance of regularity and stability could merely reflect how our brains are structured – the way our neurophysiology functions – which makes us perceive the world in psychologically viable manner, in other words, so that we aren’t constantly unsettled by how chaotic the universe is? Basing our decisions on past experiences may be problematic, and sometimes lead to erroneous conclusions, but it helps us out every single day more than it misleads us. This does not mean, however, that we can use induction as a tool to infer any sort of ‘laws of nature’.

Bob: Regarding your question, I feel that we are inseparably a part of nature, so when we examine nature, it’s important that we don’t exclude ourselves from what’s under examination. But because our brains are part of nature, if we tend to exhibit regular behaviour, this means that nature itself must be equally regularity-oriented. What you seem to be missing here is that it isn’t just inductive reasoning that makes a law what it is. There’s something more to a regularity that turns it into a law, something rooted in the world.

Sue: Well assuming the rest of nature is similar to us humans is a rather bold and risky analogy. Besides, the way the world really is entirely inaccessible to us. I side with good old Immanuel Kant – here. I don’t believe we can know the ‘thing-in-itself’. We’re only discussing ‘phenomena’ – the way things appear to us, and their observable behavior. What’s more, I can’t so easily accept that there’s something fundamental in the nature of things that links them together in the ‘lawlike’ way you suggest.

Bob: Even if we are talking only about knowing the appearances of things, my proposal can be true, because the laws of nature manifest themselves in the phenomena, and science takes up their inquiry. That way – through observing the universe – science discovers its fundamental laws, which are few and simple, as well as the results of these laws, which are numerous and complicated. But I still say that the phenomena we experience inform us about reality through scientific reasoning because both we and they are part of reality to begin with.

Sue: I feel that you shouldn’t give science credit for doing the impossible – namely understanding the hidden core of reality, the nominal world. If you claim that laws of nature exist ‘out there’, and the task of science is to discover them, then your thinking has gone astray. It’s a matter of pure luck that the human activity called ‘science’ has had the success it’s credited with having! What’s more, the theories and ‘laws’ it uses are mere instruments – they’re just conceptual tools the scientists employ simply because they’ve been effective so far. But there’s no ‘natural guarantee’ that the sun will rise in the east tomorrow morning. Likewise, there’s no guarantee that the ‘universal law of gravity’ will continue to pull us to the center of the earth even in the next minute. All we know is where science’s idea of laws has worked so far, as far as we can see. We behave as if they’ll continue to do so because that’s how our neurophysiology propels us to behave; but there’s no epistemological guarantee of any sort to justify our behavior.

Bob: I don’t agree with any of that. We have at least a minimum understanding of how the world really is, and some of that understanding is provided through our discovery of the laws of nature. That’s why scientific inquiry is the best method we have for understanding it. And I would submit that our neurophysiology indeed makes our understanding easier. It means we’re able to spot causal relations, and under many circumstances, use them to predict the future. That’s how we understand the laws of nature – thanks to the powerful tools our brains provide our minds. You shouldn’t underestimate the human mind.

Sue: Okay, so how does your powerful human mind recognize a law of nature? I’m sure there are many connections of events that seem like laws, but where it’d be an exaggeration to call them laws.

Bob: That’s a good point. You’re essentially asking how we can discern between conjunctions of events establishing causal relations which are the true laws of nature, and other less significant connections and regularities. A common example might be that day follows night. True. But day, however, is not causing night to arrive, and neither does night cause the day. ‘Day follows night’ is just a generalization of an observed accidentally true conjunction. If there were a natural causal relation between the two, the uninterrupted regularity would be a law of nature. But there isn’t, so it isn’t.

Sue: Interesting. What you’re saying is that to have a law, it’s not enough to observe regularities in the world, we have to establish causal relations. Let’s say that it’s a law that ‘All As cause Bs’. So can B choose not to happen after A? Because it seems that B inevitably follows A.

Bob: That’s exactly what it means to be a law of nature: because it’s going to happen inevitably given the right causes, no exceptions.

Sue: Is everything predetermined then? No free will? No choices?

Bob: At the physical level it seems that everything is indeed predetermined. The past determines the future because future effects have their causes in the past and the causes necessarily lead to the effects. That is what allows us to feel safe, and have a sense of universal regularity. But universal or absolute regularity is only the case with the regularities that actually are laws of nature. Other regularities, without the right causal connections to be laws, have no necessity to be repeated, just like I mentioned in the ‘day following night’ example. But true laws of nature are relatively few, and the determinism implied by them does not greatly affect our freedom to choose.

Sue: How can you say that? If the physical world is governed by laws and their products, you can’t claim that human agents are free to do as they like!

Bob: Well, if you think you’re not free because you can’t stop gravity or influence the laws of thermodynamics, then you’re in big trouble! We are free at many levels, but we cannot affect the scaffolding of nature. Imagine how dangerous it’d be if we could. Rather, our freedom has to do with numerous things which matter to us and we’re responsible for, which we create and affect within the context of the world we were born in, the people we interact with, and so on. But the very core of nature shall forever remain untouched.

Sue: You don’t seem to realize how contradictory your claim is. You’re saying that we’re free at all levels of existence, and yet there are laws we cannot affect in any way which are certainly profoundly affecting us every moment we’re alive, even determining our behavior.

Bob: Let me give you an example, and see if my argument becomes clearer. Suppose you’re an improv stand-up comedian and your show is tonight. You enter a room in which people are sitting waiting for you. There are chairs, a microphone – you know what the stage looks like. You have the idea of entertaining them, but you don’t know for sure how’s that going to work out. You have some tools, though: your thoughts, your voice, and some past experience to give you clues as to what makes people laugh. Are you free to say and do whatever you want, or not?

Sue: I’m free to say whatever I want as long as it serves the purpose of the specific job I was assigned. I’m also probably free to exit the room – given that I’ll have to deal with the series of consequences following that choice.

Bob: That’s how life works too. You’re writing the script while acting it out. The way the stage is set up doesn’t prevent you from freely running your show and defining every moment of it within its boundaries. Analogously, the way nature’s structured doesn’t prevent you from freely being yourself.

Sue: The world isn’t just a stage. The world is all that there is. And we’re trapped inside it. If laws of nature exist, then they are the chains in the prison of the world. I’d still argue that since our choices are so limited we’re fundamentally not free – even when having this conversation.

Bob: What’s a better alternative? No laws? Chaos?

Sue: All I can reply is that your ‘fundamental laws of nature’ are more likely not to exist than to exist. There are only ‘regularities of nature’.

Bob: How can you not be convinced that there are laws of nature? The universe is harmonious! If it weren’t for the laws, you wouldn’t even exist! True, sometimes we have to make some metaphysical assumptions in order to produce a system or theory. Otherwise, we’d have mere rambling.

Sue: I’m afraid rambling is better than inconsistency when trying to theorize in metaphysics. For what it’s worth, I can’t believe in metaphysical monstrosities like ‘laws of nature’. The world isn’t as tidy and predictable as you assume. Uncertainty is everywhere. You’re merely finding some temporary solace in a law-governed world because you’re a human being and the idea allows you to function or seems beneficial to you. I wouldn’t even be arguing against it if you’d just keep the ‘laws of nature’ at a lower, practical, level, that this is how things appear to work. But you insist that you know about reality what you don’t know about it.

Bob: I think we’ve reached a point where silence is better than words. In any case, the movie’s about to start, so we’d better get moving.

Eleni Angelou is a PhD candidate at the Graduate Center of the City University of New York, specializing in phil of science and metaphysics.