The brain is unquestionably the most complex organ of the human body. It is also the most important, responsible not only for keeping every other organ working properly, but our brain is also the seat of our conscious and unconscious—who we are. The brain truly is a monument to God's workmanship. Lately, scientists have made breakthrough discoveries into the workings of the brain, finally answering questions philosophers of all ages have asked, from "What is consciousness?" to John Locke's famous Tabula Rasa theory, "Are we born blank slabs?" The answers scientists are now able to give are, to no surprise, already in the Bible.

One age-old theory of the brain and consciousness is known as dualism. Dualism has its roots in ancient Persian religion, Zoroastrianism (out of which Gnosticism developed), teaching that man is composed of a holy spirit and of an evil body. The Greeks later absorbed this theory through the pre-Socratic mystic Pythagoras, who passed it on to Plato, the father of Western philosophy. In the fourth and fifth centuries AD, Augustine of Hippo, a Catholic church father, "Christianized" the pagan Plato, blending dualism with Christianity. Spiritual dualism has been a central doctrine of mainstream Christianity ever since.

However, in the seventeenth century, French philosopher Rene Descartes made the religious doctrine secular. He asserted that the mind, our thoughts and consciousness, exists in some ethereal plane distinct from the physical world. Thus, what happens to the physical body short of death, does not necessarily affect the mind, nor do thoughts affect the body. What scientists have found, though, is that this could not be more incorrect.

Spiritual dualism has had disastrous effects on Christian doctrine. Dualism has corrupted the truths of justification and sanctification, as a connection exists between dualism and the Protestant "no works" doctrine. According to this idea, all one has to do is profess his belief in Jesus Christ and accept His grace (mental actions), and one's sins (physical actions) will be forgiven. Such a person is now saved forever. This is dualistic: As long as the mind/spirit is holy, a corrupt body is of no real consequence. This idea perverts the biblical doctrine of justification by faith, narrowing the comprehensive process of salvation (justification, sanctification, glorification) to justification alone. This doctrinal reductionism turns into practical reductionism: All I have to do is believe to attain salvation, so my actions really don't matter.

Dualism also implies imperfection in God's creation, as the belief assumes an inherit corruption in the flesh, while holiness resides in the spirit. Christians who profess this doctrine seem to forget Genesis 1:31, "Then God saw everything that He had made, and indeed, it was very good." The "everything" that God saw was His physical creation, including human bodies.

This false concept causes a person to have a limited understanding of God's truth. In contrast, Jesus Christ stresses the comprehensive nature of God's way of life, as in Luke 9:59, 62: "Follow Me. . . . No one, having put his hand to the plow [commits to God's way of life], and looking back [to the life left behind], is fit for the kingdom of God." Similar remarks appear in Matthew 16:24-28, and in Luke 14:25-33, which Christ ends by saying, "Whoever of you does not forsake all that he has cannot be My disciple." It follows from His statements, in opposition to spiritual dualism, that good works are indeed necessary.

Modern science has uncovered certain qualities of the brain that can help us appreciate the all-inclusiveness of Christ's statements and understand the impact of good works. Neuroscientists conducted studies in which pianists played arpeggios while hooked up to brain-activity monitors. They found that the area of the brain that was active during the pianists' playing physically grew over time: Their work physically altered their brain, increasing their capacity to perform it.

The scientists continued the study, but removed the piano—that is, they asked the pianists to imagine themselves playing arpeggios for the same time that they actually played before—and the results were the same. Merely thinking about the work increased their capacity. These studies prove that spiritual dualism's main tenet is incorrect: Physical actions do affect the brain; the brain physically changes, affecting thought and capability; and changes of thought and capability affect the quality of actions.

While this discovery is new to the scientific community, the connection between thought and action is shown throughout the Bible in the growth of character. We can break down character growth into three stages: action, experience, and perception. Our actions become our experiences, our experiences shape and orient our perception, and our perception influences all actions. Simply put, whatever a person spends his time doing—painting, playing sports, cooking the books, or robbing banks—his actions will shape his perception of everything. An athlete will find "the game" in every day life, an artist will appreciate the subtle and the picturesque everywhere, and the thief will find opportunity anywhere he looks. This process demonstrates why good works are essential to a Christian's life.

This process also demonstrates why justification can only be through faith. Since man is born physical and without God's understanding or Spirit, his perception is based in human nature, and thus, by itself, his character can never grow beyond a human, physical disposition. Yet, when one is justified by faith and is given God's Spirit, his perception is altered by God, a process Paul explains in I Corinthians 2:9-16. No one can alter his perception of God and His truth by works in order to be justified; it must be by faith.

Justification, grace, and the Holy Spirit are tremendous gifts that God gives to His children. If it were not for these gifts, no one could perform truly good works, but we would all remain in what Paul calls the "darkness" of human understanding. Spiritual dualism, however, is a destructive doctrine in that it sees these three gifts as sufficient in and of themselves—that is, since they renew the spirit, good works are not required because they are not of any real consequence.

Jesus Christ, Paul, and God's creation all prove this to be false. God's way of life requires one to walk circumspectly, taking all aspects of life into consideration. Our good works, sacrificing for others, daily Bible study, meditation, prayer, encouraging others, etc., cause growth in character so that, with God's help through His Spirit, we can "attain to the unity of the faith and of the knowledge of the Son of God, to mature [adult]hood, to the measure of the stature of the fullness of Christ" (Ephesians 4:13, English Standard Version).