You must worship no other gods, but only the LORD, for he is a God who is passionate about his relationship with you.
“Do not make treaties of any kind with the people living in the land. They are spiritual prostitutes, committing adultery against me by sacrificing to their gods. If you make peace with them, they will invite you to go with them to worship their gods, and you are likely to do it. And you will accept their daughters, who worship other gods, as wives for your sons. Then they will cause your sons to commit adultery against me by worshiping other gods.
Exodus 34:14-16

This question generally doesn't come up around the cafeteria lunch table at work, and even the most inquisitive toddler usually won't ask it, but it's an important question nonetheless: How do you know that you know?

There's a great scene in the movie Terminator 2 where the young boy that the cyborg terminator has been sent to protect, is threatened by a couple of hoodlums. The terminator is about to blow one away when the young boy cries out, "You can't do that!" The terminator--Arnold Schwarzenegger--asks, "Why not?" "You just can't go around killing people!" the boy protests. "Why not?" "Take my word for it," the boy says. "You just can't." He knew that it was wrong to kill another human being, but he didn't know how he knew. There are a lot of people in our culture like that!

Naturalism, believing that there is nothing beyond space, time and energy, would answer the question by pointing to the human mind. Rational thought--figuring things out deductively--is one prime way we gain knowledge. Human reason is a good enough method to find out what we need to know. The mind is the center of our source of knowledge. Another way to knowledge is by accumulating hard scientific data of observable and measurable experience. This view says that the source of our knowledge is found in the senses. We know what we can perceive through what we can measure. Since naturalism denies any supernaturalism (anything above or outside of the natural world), what the human mind can reason and measure is the only standard for gaining knowledge.

Pantheism would agree with this assessment of how we know that we know. Followers of pantheism tend to put a lot of value on personal experience. The rash of near- and after-death experiences in the past few years, for example, are extremely important to New Agers. These experiences usually validate the preconceptions of pantheistic thought, which denies absolutes such as the Christian tenet that Jesus is the only way to God. The experiences of past- lives therapy have persuaded even some Christians to believe in reincarnation, even though the Bible explicitly denies that doctrine, because personal experience is often considered the most valid way to know reality.

Christian Theism says that while human reason and perception are legitimate ways to gain knowledge, we cannot depend on these methods alone because they're not enough. Some information needs to be given to us from outside the system. An outside Revealer provides information we can't get any other way. Revelation--revealed truth from the One who knows everything--is another, not only legitimate but necessary way to know some important things. Revelation is how we know what happened when the earth, the universe and man were created. Revelation is how we know what God wants us to do and be. Revelation is how we can know how the world will end and what heaven is like. Revelation in the form of the Lord Jesus Christ is the only way we can experience "God with skin on."

Naturalism's answers are inadequate, depressing, and wrong; pantheism's answers are slippery, don't square with reality, and wrong; but Christian theism--the Christian worldview--is full of hope, consistent with reality, and it resonates in our souls that it's very, very right.