Science can be defined as the unmasking of the hidden beauty of nature. Some might think that this is sentimental, if not eccentric. However, I believe it is a good and accurate definition.
The laws underlying the natural world are beautiful, and the standard of beauty, properly understood, is a good test of a scientific theory. If the proposals outlined in the theory are clumsy or inelegant in their explanatory power, it is unlikely that the theory is correct. Many great scientists have subscribed wholeheartedly to this view.
Physicists, who describe the basic nature of the world in mathematical terms, have most clearly understood and expressed this concept.
Paul Dirac (1902-1984), the British physicist and one of the founding fathers of quantum mechanics (the branch of physics that describes the behaviour of atoms and sub-atomic particles), said: "A theory with mathematical beauty is more likely to be correct than an ugly one that fits some experimental data. God is a mathematician of a very high order and He used very advanced mathematics in constructing the universe."
Many great physicists would have agreed with the sentiment expressed by Dirac, including Galileo Galilei (1564-1642), Isaac Newton (1642-1727), James Clerk Maxwell (18311879), Werner Heisenberg (19011976) and Albert Einstein (18791955).
All of them pursued an aesthetic goal in their work and knew they were on the right track when the results of their deliberations unfolded elegance, coherence and inner beauty.
When Einstein developed his equations for his theory of gravity, in which gravity is described in terms of the four dimensional space-time we inhabit, he felt particularly confident he was correct because of the simplicity and consistency of the equations.
Like any good work of art, the whole thing felt right.
The truth of beauty applies in the biological world no less (probably more) than in the physical world.
I am a biological electron microscopist, which means that I study the structure of cells and molecules at very high magnification in the electron microscope.
Unfortunately, living cells cannot be examined directly in the electron microscope, which internally has a high vacuum and high radiation environment. The cells must first be preserved and stabilised by pickling them with chemicals in a process called fixation.
Sometimes the fixation introduces spurious and damaging effects, with the result that the structures one sees in the microscope are artefacts of fixation rather than genuine reflections of living cellular structures. Consequently, the microscopist must develop a wary eye capable of discriminating artefact from true structure.
Microscopists find that the most reliable guide to true structure is a sense of the aesthetic. Cells that are well preserved and whose structures reflect true in- vivo structures are pleasing to the eye. Invariably, coarseness, sharp discontinuities and empty areas are indicative of fixation damage.
The general biological world is very pleasing to the unaided eye, as a stroll through almost any part of the Irish countryside readily confirms. This beauty of form extends down to the cellular level as revealed by the electron microscope.
Indeed, many of the structures revealed by the microscope are extraordinarily beautiful, so much so that it is surprising (as remarked to me recently by Prof David McConnell, Department of Human Genetics, TCD) that such beauty does not seem to have inspired any modern painter or sculptor.
This is probably because artists are not familiar with these microscopical images. There is great scope for fruitful collaboration between schools of art and schools of biological science.
The aesthetic appeal of an image to the eye is readily appreciated, but the meaning of beauty is far from obvious when the concept is applied to a scientific theory or to scientific equations.
I believe that a scientific theory is beautiful when it reveals, in a simple way, connections or causal relationships between parts of the natural world that remain entirely hidden to ordinary level of inspection.
Such a theory will not have to strain to explain something.
It will have a pleasing feel of balance and poise - it will "feel right", just as a painting feels right when subject, colour composition, balance and perspective come together in just the right way.
The theory of evolution by natural selection in biology is an excellent example of a beautiful theory. The basic idea is very simple, but it has the power to unify and make sense of the vast array of biological diversity and to show how everything is connected in the vast web of life.
The theory proposes that all existing species of life are descended with modification from pre-existing species.
The engine that drives this descent with modification is natural selection. Individuals in any species that happen to bear hereditable traits that confer a reproductive advantage in their particular environment will reproduce more successfully than their fellows. Consequently, their particular traits will be naturally selected and spread throughout the population.
Armed with this insight, we can see why the four limbs of the human, crocodile, dog and flying fox all share a basic structural design with a horse. These animals are each descended from a common ancestor.
The theory of evolution by natural selection passes the test of beauty, but, of course, it is also supported by a vast amount of observational and experimental evidence.
The power of a scientific theory to explain observed facts is the ultimate test, but, as Dirac pointed out, when two competing theories can each explain the facts, the more beautiful theory is usually the correct theory.
William Reville is a Senior Lecturer in Biochemistry and Director of Microscopy at UCC.