Last year I happened to find myself in conversation with a professor of linguistics. He asked me what I did. He wasn’t satisfied when I said I was a philosopher and proceeded to ask me what exactly I worked on. I never find that easy to answer so the simplest thing was to say “causation”. This provoked a somewhat dismissive response. “Harrumph!,” came his reply. “I don’t believe in causation.”

“What?” I gasped. “How can you not believe in causation?”

“I think it’s just a social construct,” he explained, adding “There’s just the flux of experience. We then impose a causal structure on it in our social practices.”

Now I like to think I’m a progressive and enlightened thinker. I am of course open to the idea that some things – if not many things – are socially constructed. Money, for instance, is real; but only because we have made it so in what we do as a society. Without people, and without a society, there would be no money. But could causation also be like that?

This challenge worried me for a while. My own work over 20 or more years has been situated squarely within the realist camp of metaphysics, especially as it concerns causation. I have developed a view in which causation is taken to be real irrespective of our attitude towards it or knowledge about it. I am comfortable with the idea of there being some causal powers of which we know nothing, which can come and go and never even manifest themselves in observable events. So the idea of causation being a social construction, were it to be true, would suggest that my entire work on causation has been a waste of time: a misguided folly.

This consequence being so dire, I set to thinking about the issue afresh. Could causation really be socially constructed? Would it have had no existence unless we had made it? Will it cease to be when humanity dies out or if we simply change the way we understand the world? Answering these questions with a yes would be a challenge to some of my core beliefs. But are there any arguments I could call to my aid?

I will not detain readers with every twist and turn in my considerations subsequent to this conversation. It need only be said that I finally saw that the challenge could be met. We had good grounds to take causation to be real: indeed, as the bedrock of our philosophy. Causation should rightly be considered as the most fundamental connection and very much part of the mind-independent reality, irrespective of social practices.

Reason suggests that the following reply is available. My opponent’s view was that causation was merely a social construction. But what is this claim? First, it is a claim that causation is socially constructed. But construction is a causal term. So the claim is that causation is brought into being, made, created by, our social practices. I cannot understand this as anything other than a causal claim. Indeed, if there is no causation, I do not see how anything can be socially constructed. Social construction requires causation.

Of course, my opponent is unlikely to give up the stance easily. I can imagine a counterclaim that when the constructivist invokes construction, in social construction, they do not mean it in any strongly real sense. They mean, again, that this is simply how we as a society understand causation. Thus causation, or construction, is also itself constructed.

But then I fear that the view they promote dissolves into incoherence. I was at first asked to accept that causation was socially constructed. But next I would be told that causation has not literally been socially constructed. Rather, the revised view is something along the lines that we have come together as a society to agree that we have constructed this thing. We haven’t ‘really’ constructed it, because that would require the reality of a form or causation that my opponent’s position denies. Furthermore, my opponent cannot say either that causation becomes fully real, society-independent, once we have constructed it. Again, the prior reality of causation would be needed for us to get to the point where causation can become real. So this looks like trouble for the view that causation is only a social construction. How can it be so without the existence of real, mind-independent causation?

The point is doubly powerful. For causation is also said to be socially constructed, that is, constructed by a society. A society, as I understand it, is more than just a plurality. What turns this into a society is that it’s an interacting plurality. And the notion of interaction is, again, an obviously causal notion. The individual members of a society affect, and are affected by, each other. How can they do so unless causation is real? I take this to be absolutely essential to the very idea of the social. There would not even be a need to invoke the social in explanation unless there are things that change by their interaction, and would not do so unless they interacted, for otherwise the sum of discrete individuals would suffice. It is therefore only through causation that the social is put into the plurality, saving its members from being solitary and self-contained. The very existence of a society, which of course I accept, is thus a proof of the reality of causation. Taking some Latin liberties, I summarise this argument in the terms societas ergo causalitas. If there is society, there is causation.

I confess to holding for some time a self-satisfaction that is rarely a good thing in philosophy. But it looked as though I had found my bedrock. I had completed my immediate task. I had answered my opponent’s charge that causation was a social construction. This could even be put in the form of a reductio argument, for if causation is not real, nothing could be socially constructed. Or we might say that for anything to be socially constructed, there must be at least one thing that isn’t; and that is causation. So this argument is significant and supports the general realist approach I had been taking during my work in metaphysics.

There was an eventual realisation, however, that as powerful as this original argument could be, it can be made still more so through that addition of two further stages.

In the first instance, among those things I take to be socially constructed is language. One way of understanding Wittgenstein’s private language argument is that it requires an interacting plurality in order to make a language. Language is a social phenomenon as much as any. In this case, meaning is normative. A solitary individual could not be a language user because they could not know whether they were using a word correctly or not. Other language users are required to enforce the norms of the language. We have already seen that if there is a society, then there is causation. And if language is an essentially social phenomenon, then we can conclude from the existence of language to the existence of a society and thence to the existence of causation.

The final step in my complete argument could also be contended though I will not here deal with every possible discussion. I am of the view that much of thinking – cognition – requires language. Now some think that there can be non-cognitive content in the mind: perhaps sensations or raw feels. I am sceptical about this though I acknowledge it is a cornerstone of empiricist philosophy, which takes it that our concepts are built from such data of raw experience. I need not enter into that debate because all I need claim is that some cognition is conceptual and I take that to mean that it is language-like, if not straightforwardly requiring language use. There are many things I can think only because I have the concepts or words for them, for example, when I wonder what suit I will wear to my meeting on Thursday morning. The final step in the argument, therefore, is that if there is cognition, then there is language. Much more can be said about this argument but I hope that the reader sees at least some attraction to it.

Each link in the complete argument now revealed, we can put them all together in their proper sequence to form a chain of reasoning. If there is cognition, there is language. If there is language, there is a society. And if there is a society, then there is causation. The argument then goes through: cogito ergo causalitas. From thinking, I know that causation is real. It is. It exists. And even though I have reasoned to causation from the existence of my own thought, and before that from the existence of society, the conclusion is not that causation in any way depends on these things. It is the opposite. Real, mind-independent and society-independent causation is a pre-condition of there being any thought and of there being any society. Thinking, language and society depend on there being causation. And given that these evidently do exist, then so too does causation.

I am of course aware that Descartes thought he also had a powerful argument: that cogito ergo sum. But his argument was inadequate in several ways. To be brief, for these issues are well known, if one asserts I think, therefore I am, then the premise assumes the very thing – the I – which the conclusion purports to prove. The argument cannot, therefore, demonstrate the existence of the individual subject, on pain of circularity. Suppose one moderates his cogito argument, claiming only: cogitation, therefore existence. Now this argument, shorn of it its I, is even less useful. Without the subject figuring in the argument, it amounts to an inference from cogitation exists to something exists. This is an argument so weak as to have no practical value.

But these complaints against Descartes are not the biggest. More the concern is that so-called Modern Philosophy has departed from this wrong starting point. Individual experience was (wrongly) taken to be the fundament – to be the thing of which one is most sure –and the measure against which all else had to be justified. Hence, Hume’s attitude to causation was that it had to be explained in terms of experience (I will set aside Hume’s denial of a subject of experience) and this led to a psychologised account of causation. Causation was reduced to an Idea based on experience of constant conjunction, temporal priority and contiguity. This gave us a habit of expectation, so we were told, but there was no real causal connection in the world upon which that habit was based. It has been recognised that there is similar weaknesses in this psychological constructivist account to the one I developed against a social constructivist theory of causation. How could Hume’s account work without a prior reality to causation?

There have been three great periods in Western philosophy: Ancient, Medieval and Modern. What I have seen of philosophy courses in the Anglo-American tradition suggests that we teach our students something like 90% Modern philosophy, in which I am including its contemporary continuation. But because it comes from Descartes’ starting point, Modern philosophy is revealed as the weakest of the three periods. Descartes doesn’t really get outside of his own mind: at least not without a succession of spurious arguments that were quickly called into question. All else was to rest ultimately on this foundation: even causation was secondary and viewed as something constructed. The new cogito argument – cogito ergo causalitas – has the advantage of taking us outside our minds. It proves the existence of something that exists independently of us and even of our social practices. Placing causation at the centre would mark a slight return to those Ancient and Medieval traditions. But Modern philosophy originated in Descartes’ wrong turn. The new cogito is the better point of departure.

Stephen Mumford is Dean of the Faculty of Arts at the University of Nottingham and Professor of Metaphysics in the Department of Philosophy. He is currently working on free will with Rani Lill Anjum, writing a book called The Power To Will for Oxford University Press.