We have been born into a world where science progresses. Discovery follows discovery. We have never known anything different. But it was not always so, and more importantly, it will not remain so. Science will one day grind to a halt. Not, I hasten to add, the applications of science. Applied science and technology will doubtless continue indefinitely. But not the discovery of the basic laws of physics, or the nature of space, time, and matter, or the structure and development of the cosmos -- science that is truly fundamental.
Do I hear you groan: 'Oh, not another prophet of doom claiming that science is finished! They were saying that at the end of the 19th century -- before the discovery of relativity, quantum physics, elementary particle physics, and modern cosmology.' No, I am not saying that. I foresee many years, or decades, or possibly even centuries of exciting, fruitful new developments. All I am pointing out is that one day these endeavors will fizzle out. And that will not be when we have discovered everything, leaving no unanswered questions. It will happen when we have discovered whatever is open to us to understand -- which is not the same thing. I suspect that we, or more likely our descendants, will be left with many tantalizing questions destined to remain open.
Why? Three reasons come to mind. First, we have to consider what we do our science with. Our brain, obviously. But how do we come to have a brain? It was something that evolved over time in response to our ancestors need to find food, shelter, a mate, and avoid predators. It was part of their survival kit. What justification can there be for claims that this imperfect instrument will be capable of answering all questions? Secondly, there are practical considerations to take into account. The largest particle accelerator built so far is the Large Hadron Collider at the CERN laboratory in Geneva, where I used to work as a high energy physicist. It is 27 kilometers in circumference. As a general rule we have found that whenever one goes for a bigger and more powerful accelerator, discoveries are made that could not have been anticipated. Why, therefore, should we assume that a machine capable of unlocking the last vital piece of evidence that completes the picture should happen to coincide with what we humans on planet Earth are able to afford or could physically build? Today's most popular theory is that the ultimate constituents of matter consist, not of point-like particles, but of tiny vibrating strings. Unfortunately these strings are thought to be so small that it would need an accelerator the size of a galaxy to see them. Clearly not feasible.
Finally, there are deep questions facing science today which have been around for so long, and are of such a nature, as to make one at least entertain the possibility that we might, for those particular lines of investigation, have already come up against, what I call, the boundaries of the knowable. The major part of my new book, "The End of Discovery," is devoted to introducing the lay person to these deep questions, and examining which of them might not be open to an accessible answer.
How will we be able to confirm that fundamental science has indeed come to an end? The short answer is that we will not know. There is no way of decisively proving that a question is unanswerable. But that will not stop certain questions, in reality, being just that -- unanswerable.
Why have I written this book? Is it to belittle science? Of course not. I am as much in awe of the achievements of science as the next person. Moreover, I have enormously enjoyed my life as a research scientist. The first thing I whisper into the ear of each new grandchild (16 so far, and still counting) is ' E = mc2'. It is my rather pathetic attempt to subliminally influence them to follow in my footsteps and take up a career in science.
Nevertheless I do get concerned when I hear some of my colleagues making outrageous claims that some day science will have the answer to all questions -- that there are no limits to the scientific endeavor, and all other forms of thought and discourse, such as philosophy and theology, are to be discounted. Such misguided arrogance does science a disfavor.
Finally, I hope my book will help readers to appreciate how immensely privileged we are to have been born into this relatively brief transitional stage of human development known as the scientific age. Let's make the most of it -- while it lasts!