Out of Newton's laws, his first is not only the hardest for people to remember from school but also the most mysterious. At a first glance it seems almost redundant, and you wonder why Newton put it there. In this piece Daniel Hoek examines the First Law and shows how our collective misunderstanding of it seems to have stemmed from an unfortunate mistranslation.
Newton’s First Law is a lie! That is to say, the principle that everybody calls “Newton’s First Law”, the one they tell you about in school, the one physicists and scholars have for centuries attributed to Newton –– that principle is not Newton’s First Law. It is a clumsy mistranslation of the Latin principle that Isaac Newton labelled the First Law of Motion, an eighteenth century mistake that somehow managed to fly under the radar.
But before I go into that, let me back up a little to remind you of what Newton’s First Law is supposed to say, and to tell you about the time I first knew something was up.
As long as a moving object is left alone (and is not yanked or pushed or tugged by any external force), it will keep on going at constant speed in a straight line forever –– that’s Newton’s First Law as it is normally understood. To me, like most people, this principle did not ring true right away when I was taught it in school. After all, if you kick a ball or a shopping cart, then leave it alone, it won’t keep moving in a straight line forever!
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