In 1895, D.D. Palmer performed his first adjustment on a janitor, Harvey Lillard, who had been deaf for 17 years. After being adjusted his hearing returned, and the modern recorded history of chiropractic began.
D.D. Palmer believed that all disease was caused by autosuggestion (thoughts), toxicity or trauma. The primary cause being thoughts. He was working with a quantum concept before the term quantum mechanics was ever used (first used in 1924). These 3 causes of disease all interfere with the body functioning at full capacity.
From the time you you were born, your Inner Wisdom (chiropractors call this Innate Intelligence) guides us to adapt to our environment in order to survive. It knows how fast your heart should beat, how often your lungs need to breathe, how to digest food, how to eliminate waste and much much more. All of this is done without any thought.
Your brain communicates with the rest of your body through the nervous system. This communication highway is protected by the spine. If the communication process is slowed down (interference), your body becomes less efficient, which leads to a state of dis-ease and eventually to disease. Chiropractors detect and remove this interference by using specific adjustments (spinal corrections) to restore the communication between the brain and the rest of the body.