There are two major philosophies that shape beliefs about health: Vitalism and Mechanism.
Chiropractic reflects the principle of Vitalism; the core of this philosophy is that life itself is intelligent. The intelligence that built you from an egg cell and a sperm cell into a fully functional whole human being that can think, love, digest food, and more, is also able to heal itself. Chiropractors call this inborn potential for self-regulation and healing of the body " innate intelligence" which means inborn wisdom. Doctors cannot create life but can help the body utilize its potential for healing and growth; it is the body and the life force within that does the healing.
This is a philosophy of health-care, with a goal to help the body to achieve optimum health and maintain it. Chiropractors understand that their role is to facilitate or support that process.
Western medicine has its roots in a philosophy called Atomism, or Mechanism. This philosophy supports the belief that the body is a machine, simply a structure of its physical parts which can be fully explained and "fixed" through the laws of physics and chemistry. This type of curing works from the "Outside-In," and doctors typically use drugs and surgery as the primary mode to treat patients. This is a philosophy of disease-care; one that addresses the body's function only when it is overtly diseased.