Final answer:
Phillip Pinel's main contribution to the care of those with severe mental illness was the introduction of humane treatment and the removal of physical restraints.
Step-by-step explanation:
The main contribution of Phillip Pinel to the care of those with severe mental illness was the introduction of humane treatment and the removal of physical restraints. Pinel advocated for a more compassionate approach to mental illness, treating patients with dignity and respect. He believed that mental illness was not a punishment, but a medical condition that required proper care and treatment.