Henry Louis Le Chatelier

Henry Louis Le Chatelier (1850-1936) proposed a general principle in chemistry called Le Chatelier's Principle. The concept is easy to grasp because it is so intuitive:

If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established.

 The principle has even broader implications, embodying the pendulum shifts in culture and politics:

Any change in status quo prompts an opposing reaction in the responding system.