Tag: Philosophy in the Middle Ages

Articles

The medieval principle of motion and the modern principle of inertia

Aquinas’s First Way of arguing for the existence of God famously rests on the Aristotelian premise that “whatever is in motion is moved by another.” Let us call this the “principle of motion.” Newton’s First Law states that “every body continues in its state of rest or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.” Call this the “principle of inertia.