When Aristotle claimed that humans differ from other animals because they have the ability to be rational, he understood rational to mean that we could form our views and beliefs based on evidence, ...

The Indigenous peoples of the Bolivian highlands are survivors. For thousands of years they have lived at altitudes of more than two miles, where oxygen is about 35 percent lower than at sea level.

In 1859, Charles Darwin’s theory of evolution was postulated in “On the Origin of Species.” In this theory, Darwin suggested that evolution occurred gradually, although there were no complete fossils.