The twentieth century was supposedly the century of physics and the twenty-first century is that of biology. Where does chemistry fit in? The answer is, in both. Chemistry was integral to both the physics and biology that dominate their respective centuries. It has played a major role in human existence for as long as civilization has existed. And it continues to be a central part of much of scientific progress. The reason why chemistry does not seem to conspicuously make its way into the lexicon of cartographers of science is the same reason why the people who do the lights, costumes, event management, casting, musical score, special effects and cinematography for a major motion picture don't figure on most people's radar. That's because their work is so ubiquitous and subtly pervasive that we take it for granted. And often enough chemistry surprises us by stepping into the shoes of the director, actors and writers.

Chemistry is a many splendored thing

I am a chemist. I am passionate about chemistry because of its central and tremendously diverse role in the entire scientific enterprise. Chemists can be doctors, inventing drugs and materials for medical implants. Chemists can be architects, designing materials that can confer resilience, strength and aesthetic shapes to building materials. Chemists can be physicists, calculating structures of molecules using quantum mechanics and shining lasers on them to interrogate their properties. Chemists can be astronomers, literally studying star stuff. Chemists can be climate and energy scientists, studying the impact of climate change on the carbon cycle and developing new materials for solar capture. Chemists can be biologists, probing the fundamental basis of life and its origins. Chemists can be chefs and perfumers, concocting uncanny approximations of natural fragrances and flavors for haute cuisine. Chemists can even be fashion designers, developing novel textiles and colors for the latest season. And chemists can be engineers in a very fundamental sense, building molecules atom by atom.

There are chemists and there are chemists

Images of chemists inevitably conjure up slightly bug-eyed scientists with unkempt hair holding green frothing liquids. But as with some other portrayals of scientists in popular sources, this image is simplistic at best and a caricature at worst. Reality is more diverse. How would the scene look like if you collected chemists from all specialties, put them together in a room and asked them to practice their trade? Many chemists would appear in front of fume hoods, specialized enclosures that are designed to suck out noxious fumes and allow a chemist to organize his or her wherewithal. You would indeed see some of them holding colorful, bubbling liquids - and this visual aspect certainly contributes to the allure of chemistry - but you would see many others holding tiny vials with colorless liquids or solids. The contents of those vials could range from DNA to snail toxins to new materials for solar energy. You could also see chemists experimenting with lasers, electronics, x-ray machines and spectrometers and they would still be doing chemistry. Tucked away in a corner, you would then improbably find a few chemists wearing neither lab coats nor tinkering with any kind of chemical apparatus. Instead - and this happens to be my trade - they would be intently staring at a computer screen, watching and manipulating 3D images of small molecules and proteins, writing code and running calculations on the structure and properties of these molecules. These people are still doing chemistry. Finally, there's a small but significant group of chemists who you would not locate in this room; you would find them instead scattered thousands of miles away in rainforests, oceans and the arctic expanse. These chemists are digging deep into the soil, studying amphibians and scooping water in search of new drugs. Others would be testing water, soil and air samples for environmental pollutants.

Chemistry permeates our world

The foregoing discussion exemplifies the sheer diversity of chemical science and its practitioners. The heart of chemistry is the science and art of synthesis, a process that can make novel molecules which never existed before. The impact of this activity on human civilization is hard to overstate. Look around you. Every single bit of material entity that you see has either been synthesized in the flask of a chemist or is a natural compound that has been modified in the flask of a chemist. Even if it is not synthetic, it has probably undergone some kind of synthetic modification that has improved its color, flavor, smell, toughness, flexibility, softness, durability, conductivity, or aesthetic looks. Much of the modern world as we know it in the form of metals, plastics, fibers, drugs, detergents, pesticides, fuels, medical implants, food and drink is the direct result of chemistry. Pondering just one of chemistry's myriad creations like jet fuel or PVC or aspirin should convince us of its all-pervasive role in human civilization. It would not be a stretch to say that chemistry's influence on our modern way of life and the rise and fall of nations is equal to that of the development of the calculus.

Saying that chemistry has been influential in the rise and fall of nations is not an exaggeration. There is no other science whose basic entities have had such an impact on international and domestic geopolitics on an individual basis. Time and time again, single molecules have dictated the fate of nations. The central role of iron, bronze and aluminum in the shaping of ancient and modern cultures is well-documented but there's more. For many years and even now, the economic strength of a country has been judged by its production of sulfuric acid. Or consider morphine, that singular substance which is alluring and forbidden in equal parts. Morphine was responsible for the Opium Wars, a set of conflicts whose repercussions forever changed the geopolitical landscape and future of China. And in a classic case of very slightly altered chemical identity which we will often explore on this blog, morphine's cousin heroin continues to hold enormous sway on political calculations through the drug trade, leading to entire communities destroyed and billions of dollars spent. The pattern repeats throughout history; indigo, saltpeter, crude oil, rare earth metals, uranium, ambergris, gold, turmeric, silk, salt, all of them substances prized for the presence of one or a handful of molecules, sometimes prized enough to have encouraged trade, caused wars, brokered peace, killed millions, driven men to wealth, madness and despair.

The human science

As I noted in a past post, it's this intimate connection of chemistry with our world and history that makes it, more than any other discipline, the human science. This has led to a complicated relationship between molecules and our collective consciousness. It is not uncommon for the media to try to steer us clear of the dangers of "chemicals". What's usually missing is the context. Sometimes the belief that all chemicals are bad leads to nonsensical advertising, such as the enthusiastic marketing of products that apparently contain no "chemicals", a practical impossibility if chemicals are defined as molecules of one kind or another. One of the common refrains of those battling this chemophobia is that "the dose makes the poison", a universal principle that applies to everything from water to botulism toxin. Many well-intentioned studies which seek to warn the public of the dangers of chemicals ignore this basic fact and often miss details of exact doses, statistical significance and sample sizes.

Nonetheless, much of this chemophobia reflects the complicated relationship between humans and science that we have always lived with. In this sense chemistry presents us with a microcosm of the tussle between technological progress and its moral dilemmas; after all, while penicillin brings a person back from the brink of death, nobody can deny that it was also used to kill during World War 1, and it is true that wrong doses of chemicals in the wrong hands can cause much death and suffering. Seen this way chemicals are no different from human beings where the specific context can turn a saint into a sinner. But these facts present us with a challenge that's no different from that presented by the progression of science and technology since the industrial revolution. Remembering Joseph Rotblat's words that much of human suffering is related to the time lag between technological developments and our moral and human capacity to fully comprehend them, for better or worse we will continue to be confronted with chemicals, with fossil fuels, with radioactivity and with genetic engineering. In many of these cases however, it is hard to deny that their sum total has greatly contributed to economic and technological progress and has objectively alleviated suffering, at least in some cases like drug development and poverty eradication.

Chemistry@TheCuriousWavefunction

On this blog I will be discussing the nature of chemical science. I will be talking about the history of chemistry and will try to illustrate the incalculable impact that molecules have had on our way of life. Papers will be discussed and the power of basic chemical concepts will be illustrated. Along the way we will meet some of the giants of chemistry on whose shoulders we all stand. Another goal is to discuss the unique philosophy of chemistry, something that has traditionally been neglected by philosophers of science. The overall aim is to point out the central place that chemistry has in our world and to demonstrate that it is very much the human science.

This blog picks up the baton from my old blog with the same name which I have been writing for slightly more than eight years now. That blog has been an immensely rewarding endeavor and has been enriched with comments and criticism by readers, many of whom have paid more attention to it than it deserved. Here I will also be dwelling on my other interest, the history and philosophy of science as well as miscellaneous scientific topics that I am interested in. I am thankful to the organizers of the Scientific American blog network (especially Bora Zivkovic) for this opportunity and am very happy to be joining a first-rate group of bloggers who between them seem to cover almost every field of human inquiry. I hope I can make my own modest contribution to the sparkling dialogue that defines this site, and I greatly welcome and appreciate comments and criticism.