According to Attia, medical history comprises two distinct eras. He calls the first era “Medicine 1.0.” Medicine 1.0 began with the Greek physician Hippocrates (c. 450-c. 380 BCE) and lasted 2,000 years, until the late 1800s. In Medicine 1.0, observations and guesswork served as the basis for medical conclusions rather than science. A major component of Medicine 1.0 was that bad air (also called “miasmas”) or evil spirits spread disease.

The groundwork for the shift from Medicine 1.0 to Medicine 2.0 began with English philosopher and statesman Sir Francis Bacon in 1628, who was the first to set-up experiments to test hypotheses. Attia notes that “this represented a major philosophical shift, from observing and guessing to observing, and then forming a hypothesis” (27). Three centuries elapsed, however, before experiments and hypothesis testing became widespread in the medical field.

Medicine 1.0 shifts to Medicine 2.0 with German physician and microbiologist Heinrich Hermann Robert Koch’s discovery of the germ theory of disease in the late 19th century. Koch discovered that microscopic organisms (such as germs) caused specific diseases. New technology (e.g., the microscope) and a new way of thinking prompted this shift. The importance of Medicine 2.0 cannot be understated: Medicine 2.0 represents a “defining feature of our civilization, a scientific war machine that has eradicated deadly diseases such as polio and smallpox” (27).