Let's kick off the International Year of Chemistry with one of those somewhat pointless but endearing and endlessly entertaining questions: Who was the greatest chemist ever? Paul@Chembark and the Nature Chemistry crowd have dived into the discussion by conducting informal polls.
Linus Pauling seems to be voted at the top by common consensus. But to me the lack of agreement on the other names seems to be both a tribute to the diverse nature of chemistry as well as an indicator of problems with its public image. Consider the numero uno himself. Rather than making one single, very deep contribution like Einstein's relativity or Heisenberg's uncertainty principle, Pauling became the greatest chemist ever through the sheer variety of contributions he made to disparate branches of chemistry: the quantum mechanical basis of chemical bonding, the structure of crystals, the structure of proteins and the molecular basis of genetic diseases to name a few. Some of these contributions do stand out for their depth but the name of the game here is "diversity" which is at the soul of chemistry. Pauling's contributions as well as his status as the leading scientist in his field also highlight the problems with the public perception of chemistry- the fact that the field lacks "big problems" which can be latched on to by the public imagination. For physicists it's the origin of the universe, for biologists it's evolution. But chemistry is usually seen as a utilitarian and enabling science which contributes to revolutions in other fields but lacks deep, defining questions of its own.
However I beg to slightly differ here. There is in fact one problem, as deep and fundamental as any in physics and biology, which is essentially chemical. This problem is the origin of life. Life started out unquestionably as a molecular event. Other disciplines certainly bear on this problem in important ways but the way the origin of life started off constitutes a quintessentially chemical conundrum. Darwin took off where chemistry left off; ironically it is the first step that's still the big mystery while the succeeding steps have been worked out in spectacular detail. More broadly, the origin-of-life problem boils down to the problem of self-assembly which is also important in other applied areas like protein folding and nanotechnology. So if chemists want to really pitch an abiding single problem in their field with important repercussions for the human race to the public, they cannot do better than the origin of life and self-assembly. They could start with origins and end by talking about amyloid, Alzheimer's disease and supramolecular circuits, covering a vast scientific landscape which demonstrates the reach and impact of chemical science.
But back to the greatest chemist ever. At its heart chemistry is an experimental science, more so than physics where mathematical elegance may play roles which are as important as experimental observations. Any list of greatest chemists should include some of the great experimentalists in the field, people whose contributions led to techniques that revolutionized the reach of chemistry. In the list of greats cited by the others, one name seemed conspicuously missing to me- that of Fred Sanger. Not only is Sanger the only person to win two chemistry Nobel Prizes, but the techniques that he discovered- protein and DNA sequencing- underlie all of modern biochemistry and the genomics revolution. If you want to make a case for a chemist fundamentally altering the progress of human life, Sanger is as good a case as any and his absence on the lists is surprising and regrettable. One can also talk about Kary Mullis and PCR, but Sanger's contributions encompass a much wider swathe of basic science.
If chemistry as a science has been driven as much by techniques as ideas, one can also talk about the pioneers of x-ray crystallography and NMR spectroscopy in the list of greatest chemists. However, since these contributions were necessarily group efforts it's not really possible to single out individuals, although people like Perutz, Bernal, the Braggs and Hodgkin are certainly worthy candidates. Chemistry as a science is also uniquely distinguished from other sciences by its ability to make new things, so the inclusion of synthetic chemists like Woodward and Fischer is mandatory and has duly been acknowledged. With exciting developments in protein and nano-material design looming on the horizon, who knows what new creatures would populate this traditional looking roster of synthetic giants in the future.
The fact remains that chemistry is much too diverse to be pigeonholed into narrow "big idea" boxes. But rather than bemoan this fact, chemists should proudly wear it on their lapel since it demonstrates the exhilarating possibilities inherent in chemistry's expanse. An expanse which announced its presence with the origin of life.