Karl Popper was one of the most influential philosophers of the twentieth century. Widely considered to be the father of modern science, Popper introduced the principle of falsificationism which states that for a theory to be considered scientific, it must have a hypothesis which is falsifiable, or capable of being disproven. A theory with a hypothesis which cannot be disproven, like the belief that God created the universe in seven days, is not rightly understood to be a scientific theory.

Popper turned his attention to political philosophy during the Second World War, culminating in the publication of The Open Society and Its Enemies in 1945, where Popper offered a defence of liberal values, famously stating that “We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.”

Jason McKenzie  ...