The British empiricists and the French Sensationalists of the Age of Enlightenment all had in common the belief that all knowlege comes from experience - that there are no innate ideas. They all used occam's razor against metaphysical constructs - if matter and motion could explain an event, it sufficed as the sole explanation for an event.

These thinkers held that all knowledge, even moral knowledge came from experience. (See David Hume.) For this, these thinkers were often labeled "atheists" although many of them, such as Hume and Paine, were actually deists. Yet, as bold as these thinkers were, none of them dared to work out, in detail, just how this learning took place. It was up to the thinkers of the 19th century, such as John Mill, Bentham, and John Stuart Mill to take a shot at it.

In the 17th and 18th centuries, a scientific belief in simple linear determinism began to grow. This determinism, born of the works of Isaac Newton, came to full bloom in the works of mathematician Pierre Simon Laplace.

As the successes of these physical and mental sciences spread throughout Europe, and as religious doctrine became increasing suspect from the time of the renassaince, a new belief emerged that science could solve all human problems. This belief would become known as scientism.

Those embracing scientism held that only scientific knowledge was valid knowledge. Two such men are Comte and Mach.