During the recent protest march against the Pope in London, I noticed one sign which read "I believe in science". This made no sense. The point about science is you don't have to believe in it. Perhaps the bearer of the sign meant he believed in the power of science to make him happy or fulfilled. Or perhaps he just meant he didn't believe in God.
Nonsensical posturing about science has become commonplace. This is caused, I think, by the triumphalist tone of the wave, now abating, of popular science books started by Stephen Hawking's A Brief History of Time. Physicists used to crow they were on the verge of a "Theory of Everything", biologists said they had cracked the code of life and neuroscientists, accompanied by certain philosophers, claimed the mystery of consciousness would soon yield.
None of these things was, or is, true. They are not true because all these problems have proved far more complex than anybody expected. But are they also not true for a more profound reason? Are they not true because they are insoluble, because the human mind is incapable of understanding the world fully?
The physicist Russell Stannard thinks this may be the case. He believes that science will eventually come to an end, and that we are living in a "transient age of human development" in which scientific discoveries can be made. But science won't end because we know everything; it will end because we know everything we can know.
Science, he says, may well not crack, among other things, the problems of consciousness and free will, the ultimate divisibility of space and time, and the true status of mathematics. It may not even be able to establish the existence of the world. An extreme interpretation of quantum theory says that because all we know of the world is obtained by our acts of observation, and because these determine the world we see, we cannot be sure of the existence of anything between those observations. In fact, strictly speaking, the world ceases to exist in this gap.
This, therefore, is an anti-triumphalist book. The more of it you read, the less you discover we know. Stannard argues that there are certain to be limits to science. This raises the further question: are these ultimate limits, or just the limits of the human mind? In other words, could a superior intelligence solve the problems? That is doubly unknowable.
But the idea of limits is important. Ever since Galileo looked through a telescope in 1609, failed to see what the Church's cosmology said he should see, and thereby established the scientific method, the march of science has been spectacular and seemingly unstoppable.
From the mid-19th century onwards, it became increasingly respectable to say that science had invalidated all other forms of knowledge - religion, philosophy and so on. As a result of the scientistic wave that began in the 1980s, this idea is not merely commonplace, it is the orthodoxy by which we live. And behind it lies a faith in the omnicompetence and omniscience of science. But, as Wittgenstein saw, this is a delusion. Even when all the problems of science have been solved, he pointed out, the problems of human life will remain untouched. In a world where shampoos have to be validated by science, people naturally find this hard to understand.
Stannard makes the idea of a limited science more accessible simply by pointing out its actual rather than its conceptual limitations. He pinpoints, for example, the critical difficulty of contemporary neuroscience - that researchers must still rely on the subjective reports of its subjects to match the pictures of the brain seen with fMRI machines with mental events. "There is nothing about these physical patterns of behaviour that in [itself informs] us that they are accompanied by someone having a mental experience."
This is a very profound problem indeed, and one that, in the current blaze of neuroscience propaganda, is easily overlooked. It is also indirectly linked to another of Stannard's potential unknowables: "the problem of understanding things-in-themselves". Kant pointed out we have no access to the noumenon, the thing itself, uncoloured by our perceptual apparatus. In physics, this leads to a fundamental crisis. Are all these elaborate mathematical models pictures of the world as it is, or merely of how we see the world?
We may suppose that because the models are internally consistent they must be true externally. However, that may be because we work so hard to make them consistent that we rig them. The standard model of particle physics, for example, is rightly seen as a great triumph of modern thought, but it requires no fewer than 19 adjustable parameters to make it work. We don't know why these figures are what they are and the model does not include gravity; as such, we can only say that it works incredibly well, not that it is true, in the sense of corresponding to anything in the world.
This is, I hardly need add, a book worth reading. Lucid and provocative, it is a very polite corrective to both the superstitions of the layman ("I believe in science") and the triumphalism of the experts.
The End of Discovery
Oxford University Press, 240pp, £14.99