Many of us desire certainty. We don’t just want to believe, or even have fairly or very good grounds for believing. We want more still: cast-iron certainty.
Our craving for certainty can make us vulnerable to manipulation and even brainwashing. As scientist Kathleen Taylor points out, cults typically exploit the discomfort we feel when we experience uncertainty. By providing a simple set of certainties that cover and explain everything, and constantly reminding us of the chaos and uncertainties that lie outside, political and religious cultists can make their belief systems increasingly attractive, and increasingly difficult to leave.
As Taylor wrote in The Guardian, “The contrast between the complicated, fragmented muddle of the unbeliever’s life and the pure simplicity of true belief is often emphasised by ideologues who understand the power of uncertainty to frighten and unnerve people who may already feel that their lives are out of control.” Taylor considers this exploitation of uncertainty one of five key signs of brainwashing.
Certainty may be attractive, but what exactly are we after? Not just psychological certainty – feeling certain that something is true. Plenty of psychological certainties have turned out to be false. Many once felt quite certain that the Earth does not move. Fred might feel absolutely certain that his wife will never leave him. No matter the strength of convictions, these beliefs can still turn out to be false.
Epistemic certainty, on the other hand, is usually supposed to provide a guarantee of truth. If you’re certain, in this sense, that your house is on fire, then you can’t be mistaken. If it turns out you’ve been taken in by an elaborate hoax involving deceptive lighting and a smoke machine, then you were never really certain your house was on fire, even if you thought you were, and even if you felt quite certain.
How can we know when we have certainty? One popular suggestion is indubitability. A belief will be certain if it can’t be doubted. Philosopher René Descartes famously tried to subject all his beliefs to doubt to discover if any were indubitable. He found that all his beliefs about the external world – including that he had a physical body – could be doubted. There might be a powerful evil demon intent on deceiving him about all these things. Descartes found he could even doubt simple mathematical truths, such as that 2 + 2 = 4, for that same evil demon could make him go wrong in even his simplest calculations. The one thing Descartes found he couldn’t doubt was that he existed. In attempting to doubt that he exists, Descartes must be thinking, and so must exist. That he existed was something about which he could be certain.
But does indubitability guarantee certainty? Suppose a brain scientist puts a computer chip in my brain that makes it impossible for me to entertain certain thoughts and doubts. As a result, I’m unable to doubt that my underwear is red. That doesn’t mean I’m epistemically certain my underwear is red. I could easily be mistaken. So, it seems that indubitability is no guarantee of either truth or certainty. If indubitability is to underwrite certainty, it’s going to have to be a special sort of indubitability.
Might we get clearer about what certainty is by thinking about proof ? People often associate certainty with proof: they suppose something is certain if it’s proved.
However, ‘proved’ is slippery term with a variety of meanings. In a court of law we seek, and often get, proof beyond reasonable doubt. But we can also set the bar far higher, demanding proof beyond all possible doubt. Set the bar that high, however, and very little is ever proved: certainly not the guilt of an accused person standing in the dock. No matter how strong the case presented by the prosecution, it’s always possible that there’s been some elaborate conspiracy to frame them. Still, as the evidence mounts, the accused’s guilt can become increasingly probable to the point where we can justifiably send them to prison for life. We can have proof beyond reasonable doubt – and reasonably suppose we know – even if we lack epistemic certainty.
One reason philosophers have been particularly interested in certainty is that they have sought an entirely secure foundation on which to build their beliefs. But what could provide such a foundation? Perhaps our immediate subjective experiences. Maybe I can’t be certain that there is a table currently before me (it’s possible I’m hallucinating), but I can be certain that I’m presented with the subjective appearance of a table. Similarly, perhaps I can’t be certain whether I have an injury to my foot, or even that I have a foot. Perhaps my foot has been amputated and I’m experiencing a phantom pain.
Still, it seems I can be certain that I am experiencing a pain, even if it’s not in my foot. It appears that the subjective realm may allow us at least some cast-iron certainties. Still, even supposing my subjective experiences can deliver some certainties, can those certainties provide an absolutely firm and unshakeable foundation for my belief in, say, an external world of trees, flowers, mountains, and stars? It seems not. After all, Descartes’ demon might be creating these appearances in me in order to deceive me about the external world.
The philosopher G.E. Moore thought the existence of the external world was certain, and offered the following ‘common sense’ proof. He held up his two hands, gesturing to one and then the other, and reasoned like so:
Here is one hand And here is another. Therefore: I have two hands.
What’s true, perhaps, is that ordinarily, outside of a philosophical setting, Moore’s argument would probably be considered an adequate proof. But to many philosophers Moore’s argument looks hopelessly question-begging. Rather than establishing there’s an external world, Moore seems to presuppose that there is one. How can Moore be sure his two premises are true? How can Moore know he’s not being deceived into supposing he is waving two arms about by Descartes’ evil demon, or a supercomputer generating a Matrix-like virtual reality? After all, everything would seem exactly the same to Moore. It appears that not only can Moore not be certain of his conclusion; he can’t even know it.
We have seen that certainty is elusive – hard to pin down, and hard to achieve. But perhaps that’s because we are confused about what certainty is. Ludwig Wittgenstein responds to Moore’s proof by insisting that both Moore and the sceptic about the external world make the same mistake. Both think that ‘Here is a hand’, used in the way Moore uses it, is used to make a claim. On Wittgenstein’s view it is not used to make a claim about the existence of a hand; rather, it’s used to fix what the word ‘hand’ means. No one ever holds up a hand in broad daylight and says ‘Here is a hand’ unless they are, say, explaining the meaning of the word ’hand’ to foreign-language students. Consequently, says Wittgenstein, “If I wanted to doubt whether or not this was my hand, how could I avoid doubting whether the word ‘hand’ has any meaning?”
The ‘certainty’ attached to such an utterance is not a particularly secure kind of knowledge about how things stand in the world. Rather, in such circumstances, the sentence ‘This is a hand’ is used to articulate part of the framework of meaning within which any such doubt might be raised. As Wittgenstein famously wrote: “The questions that we raise and our doubts depend on the fact that some propositions are exempt from doubt, are as it were like hinges on which [those] doubts turn.”
Epistemic certainty is siren-like yet elusive. I have to admit that not only am I not sure how to achieve epistemic certainty, I’m not even sure what it is.
