One of the greatest challenges facing science today is understanding the physical basis of thought. The brain is a physical entity filled with cells that interact chemically via biochemical pathways. Research during the past fifty years has made considerable progress in understanding the scientific basis for the brain activity--understanding the biochemistry of the brain. But why certain compounds produce feelings, thoughts, and memories is still an area of exploration and research.

Narcotics are a class of compounds that affect the physical brain but also alter the mind. Specifically, they are compounds that produce narcosis or general anesthesia and relief from pain or analgesia. They alter the minds perception of pain through the actions of the brain but they also induce a sense of euphoria and well-being that has not yet been tied to specific biochemical reactions. That is, the brain is the physical entity that is composed of...