Human beings have been put on this earth to create. Some write poems. Others build additions to houses, draft new civil rights legislation, dig ditches. Some make molecules--these are the chemists. All- -poets, builders, lawmakers, ditchdiggers, chemists--either create something new (call it man- or woman-made, synthetic, artifactual, or unnatural) or modify a product of nature.
Is the natural different from the unnatural? Yes, on the spiritual level, as the designers of food labels know too well. The words natural, organic, unadulterated have unmistakably positive connotations. No, on the material level. All stuff, whether natural or unnatural, is at the microscopic level molecular. And all observable macroscopic properties- -color, toxicity, strength, conductivity--follow from that microstructure, from the arrangements of atoms in space. Synthetic molecules, carefully made, can replace natural ones. Your MSG headache is equally well induced by synthetic or natural MSG, your pneumonia cured by an antibiotic made either by a mold or in the laboratory.
The natural-unnatural distinction is made ambiguous by every aspect of human existence, not just by molecules in and around us. I look out my window and see a wonderful rolling landscape of green fields and forests--the foothills of the Appalachians. It is human agriculture that has shaped that view. My roses in bloom and my neighbor’s sleek dachshund are curious and pleasing mixtures of nature and most deliberate intervention.
It’s ambiguous not just to nonscientists but even to the molecule makers, the first ones to tell people that there is no such distinction. People in the molecular trade talk of natural product synthesis--the laboratory crafting of the molecules of nature--to distinguish it from the synthesis of molecules never before present on Earth. Significantly, no chemist uses the term unnatural products, except as a joke. Even those who insist most vehemently that there is no difference between natural and unnatural, I suspect, go home to houses with windows, not photographs of landscapes on windowless walls; their furniture is made of wood, not an artful imitation.