President Lyndon Johnson was noted for coining earthy witticisms. He once put down a political opponent by declaring: "That guy is so dumb he can't fart and chew gum at the same time."
And, indeed, it is a mark of intelligence and maturity to be able to carry on different activities and employ different modes of thought at the same time and to integrate them seamlessly into our lives.
Many influential scientists, such as James Watson, Francis Crick, Richard Dawkins and Peter Atkins, supported by many loyal fans, believe science has the power to explain everything. This wildly exaggerates the power of science and promotes a grossly impoverished view of reality.
The business of science is to uncover the mechanisms that underpin the natural world, and its mode of operation is to treat the world impersonally, as an "it". The impersonal nature of science allows scientific conclusions to be independently and repeatedly tested and, consequently, to be verified or rejected.
Science has been spectacularly successful in its domain. Sir Peter Medawar, the Nobel Prize-winning British immunologist who died in 1987, described it as the single most successful enterprise of the human spirit.
Science has shown us how the world began in a big explosion, about 15 billion years ago, how the stars formed and forged the natural elements, how planets formed, how our solar system formed, how life began on Earth and evolved into the fantastic variety we see around us, how the four basic forces of nature - gravity, electromagnetism and strong and weak nuclear forces - determine everything that happens, and much more.
Science works in the material realm and seeks only material answers to the questions it asks. Although the working method of science is materialistic, this does not mean science supports the global philosophical position of materialism.
Materialism holds that the properties of matter and energy explain all that exists. Science is silent on this broader question. Many scientists are materialists, however, and take the position that science can explain everything - scientism. That there are many things science cannot explain, such as consciousness, does not faze these scientists, who claim science will explain everything given time.
I am a scientist and an enthusiast for science, but I do not subscribe to scientism and the philosophy of materialism, which, I believe, claims far more than can be justified.
I believe the claims of scientism have unconsciously led influential social philosophers to reject the legitimate claims of science to provide a trustworthy map of the natural world. I also believe these inflated claims slowly but surely alienate people.
The growth of scientism is producing some odd secondary effects. Scientists seem increasingly unwilling to express general opinions, restricting themselves to scientific opinions.
And in many cases, as so many things that come up in everyday life are not amenable to reductionist scientific analysis, such as the pros and cons of the war in Iraq, this means offering no opinion at all. The net effect is to give the impression of a gagged observer of life rather than a full participant in it.
Life is richly textured and many layered, and in order to interpret and understand the experience one must use a range of philosophical tools adequate to the task. That science, natural philosophy, has been so astonishingly successful in its domain should not blind us to the fact that it is a unique tool for its own unique domain, the impersonal realm of the world as "it". In this respect, scientism is blinded.
Most of the things that are most valuable to us have little to do directly with science. The things that make life worthwhile include the love we give and receive from family and friends, the enjoyment we feel from contemplating beautiful things, the satisfaction we get from doing work we enjoy and work that challenges our talents. And, if we are scientists, the satisfaction we get from contemplating the rational order of nature.
No scientists could lead balanced, or indeed sane, lives if they acted as scientists all the time. There is, for example, no scientific analysis of music that explains or enhances its power to move the emotions. There is no scientific analysis that can tell you whether friends really care about you or are using you for expedient purposes. But your heart knows. There is no scientific prescription for what you will find sexually attractive, but your whole person instantly recognises it when it sees it.
And there is no scientific analysis of the supernatural, because science deals only with the natural. Yet all societies believe in the supernatural realm.
These thoughts were prompted by a question put to me recently, after I addressed the annual conference of Irish science teachers on the subject of "What is science?"
The question asked if it wouldn't be somewhat contradictory for a scientist, whose professional work encourages scepticism, to believe in supernatural matters.
My answer, in a nutshell, was that scientists, like everyone else, have to learn how to fart and chew gum at the same time. William Reville is associate professor of biochemistry and director of microscopy at University College Cork