Andrew Taylor Still (August 6, 1828 – December 12, 1917) was the founder of osteopathy, he defined osteopathy as: “that science which consists of such exact, exhaustive, and verifiable knowledge of the structure and function of the human mechanism, anatomical, physiological and psychological, including the chemistry and physics of its known elements, as has made discoverable certain organic laws and remedial resources, within the body itself, by which nature under the scientific treatment peculiar to osteopathic practice, apart from all ordinary methods of extraneous, artificial, or medicinal stimulation, and in harmonious accord with its own mechanical principles, molecular activities, and metabolic processes, may recover from displacements, disorganizations, derangements, and consequent disease, and regained its normal equilibrium of form and function in health and strength.” 
Dr. Still’s founding principles:
1) The Body is a Unit
The body is considered as a whole. On an anatomical level, it can be observed that the entire body and its systems are united by means of the fascia. It is continuous throughout the body, uniting system to system and cell to cell, and by supporting and maintaining these structures enables them to work in harmony. This phenomenon is also observed on a functional level. Each part of the body has its own specific function to achieve (e.g. temperature regulation or pH balance); however, each of these separates elements works as part of a 'team' to support the overall functioning of the individual. These are all regulated by the nervous system, the central nervous system controlling the musculoskeletal system whilst the autonomic nervous system oversees the visceral function; the endocrine system controlling hormonal balance; and the immune system defending the body.
2) Structure governs function
This structure functional dependency implies predictive or diagnostic possibilities. With the understanding of body anatomy and the relation of one structure to another, it is possible to predict the change in function when there is a change in structure.
3) The Role of Artery is supreme
When blood flows freely, the tissues are well nourished can perform their physiologic functions without impedance. With the occurrence of trauma (physical or emotional), the tissues contract, twist, and compress. The fluid flow becomes obstructed.”
4) The body possesses self-regulatory and self-healing mechanisms
The body always works towards homeostasis, and possesses mechanisms to control the function of the body. These mechanisms are in constant interaction, thus enabling the body to achieve a constant state of physiological balance, known as homeostasis. However, when dysfunction occurs, the additional workload created to maintain its physiological balance is referred to as the allostatic load. Removal of the allostatic load allows the body to return to normal balance and specific effects disappear.
The self-healing mechanism employs the body’s innate ability to heal. Leveraging several body systems including immunity, nervous, endocrine and vascular systems, the body will repair itself following the removal of allostatic load caused by dysfunction or stress.
1. Still, Andrew Taylor (1908). Autobiography of A.T. Still. Kirksville, Missouri. ISBN 1150207795.