Before 1945, a “computer” was a machine built to do one thing. ENIAC, the famous wartime calculator, was programmed by physically rewiring its circuits: connecting cables, flipping switches, and rearranging plugboards. Changing the program could take days. Each new calculation required the machine to be essentially rebuilt from the outside.…

On the evening of February 3, 1892, Nikola Tesla walked onto the stage of the Royal Institution in London and proceeded to give one of the most spectacular scientific demonstrations in history. He held glass tubes that glowed without wires. He sent electrical discharges through his own body. He lit…

Before there were scientists, there were philosophers. The word “science” itself did not exist until the 19th century. For most of recorded history, the people who studied nature, tested hypotheses, and argued about the structure of reality called themselves natural philosophers. The boundary between philosophy and science was not a…

In 1690, Christiaan Huygens published his Traité de la Lumière, arguing that light is a wave. In 1704, Isaac Newton published his Opticks, arguing that light is a stream of particles. These two books, written by the two greatest physicists of the 17th century, set the terms for a debate…

In February and March of 1865, a quiet Augustinian friar named Gregor Mendel presented the results of eight years of painstaking experiments on pea plants to the Natural History Society of Brünn (now Brno, in the Czech Republic). The audience of about forty local scientists listened politely. Nobody asked any…

In 1928, a twenty-four-year-old Hungarian mathematician published a paper that would eventually reshape economics, political science, military strategy, evolutionary biology, and artificial intelligence. The paper was titled “Zur Theorie der Gesellschaftsspiele” (On the Theory of Parlor Games), and its author was John von Neumann. The “parlor games” in question were…

In 1935, the Austrian physicist Erwin Schrödinger wrote a letter to Albert Einstein describing a thought experiment involving a cat, a vial of poison, and a radioactive atom. The experiment was designed to show that something was deeply wrong with the way quantum mechanics described reality. Schrödinger intended it as…

Heights of people. Errors in measurement. Blood pressure readings. SAT scores. The weight of apples in a crate. The speed of molecules in a gas. All of these follow, approximately, the same mathematical shape: a symmetrical, bell-shaped curve that rises to a peak at the average value and falls off…

Why Cryptography Is the Most Important Subject You Never Studied Every time you send a message, make a payment, or log in to a website, you are relying on cryptography. The mathematics of secret codes protects your bank account, your medical records, your private conversations, and the infrastructure of modern…

There is no verified portrait of Robert Hooke. For one of the most productive experimental scientists of the 17th century, a man who contributed to physics, biology, astronomy, architecture, and engineering, this absence is extraordinary. Some historians believe that Isaac Newton, who despised Hooke with a ferocity that bordered on…