Alternatives Journal 35, No. 4 (2009): 8-38
by Thomas Homer-Dixon

Physics was the master science of the 20th century. Ecology will be the master science of the 21st century.

What do I mean by master science? A master science is, in part, the dominant scientific discipline of a historical epoch. It is the prototypical science of the time – the discipline that people think of first when they consider science. It’s also likely to have produced the most spectacular discoveries and technologies. More importantly, a master science generates and orders the concepts through which society understands itself and its relation to its surroundings.

Arguably, chemistry was the master science of the 18th and 19th centuries. From Antoine Lavoisier’s discovery of oxygen’s role in combustion, through Friedrich August Kekulé’s dream about benzene rings, to Alfred Nobel’s invention of dynamite, chemistry – emerging from the centuries-old practice of alchemy – produced the bulk of scientific breakthroughs during this period. It also generated the technologies of metallurgy and warfare – especially for guns, both large and small – which determined the rise and fall of the great modern empires.

In the 17th century, Isaac Newton laid the foundation for the ascendancy of physics. Although Newton’s ideas were enormously sophisticated, they nevertheless assumed that the universe resembled a machine. This machine’s behaviour was, Newton maintained, governed by laws that could be stated in precise mathematical formulae, making it predictable and potentially manageable. This notion of a law-governed, mathematically tractable, machine-like universe resonated within societies in the throes of the early Industrial Revolution, because everywhere machines were reordering economies, production processes and social relations. During the 18th and 19th centuries, physics also provided critical breakthroughs bearing on these machines’ motive power. Sadi Carnot’s analysis of the efficiency of steam engines, which laid the foundations for modern thermodynamics, was one such example.