Before the rise of modern science, people based their ideas of knowledge on religion. This idea is the religious theory of knowledge, which was most popular before the enlightenment period. The religious theory states that all knowledge comes from God. Humans are born with their knowledge, it is innate. It is the principle that God gives us a conscience at birth that we use to tell right from wrong. Although this is a common belief, some people think that you learn right from wrong from experiences. The belief that people learn from experiences differs from the original religious theory because, back then, people believed God gave us not only a conscience, but all knowledge. Even though many other theories of knowledge have been presented, people still believe the original religious theory today. .
John Locke, a renowned English philosopher, rejected the religious theory, because he said that if knowledge comes from God and God loves all of his children equally then we should all have roughly the same amount of knowledge. This brought up a solid point, but is not true because some people are much smarter than others. For example, Albert Einstein is considerably smarter than Homer Simpson. Does this mean God loved Einstein more than Homer Simpson? This was a relevant problem for religious people in that if God really created knowledge AND everyone equally, why are people more intelligent than others? And if knowledge comes from God and God is good, then all knowledge should be good and everyone should mostly agree on everything. However, people disagree on a lot of things. For example, most people believe murder is bad. Nevertheless, people like Saddam Hussein and Adolf Hitler did not feel this way. So Locke concludes that knowledge does not come from God.
Locke is considered a realist and believes there is a real world outside of us. He says we use our five senses to put ourselves in context with the outside world.