Why the familiar equal sign isn’ t just a marker of sameness but a gateway into math’ s— and humanity’ s— most profound questions
Math is famous for its equations: 1 + 1 = 2, a^2 + b^2 = c^2, or y = mx + b. Much of the time it can seem like that’ s all mathematics is: following steps to show that what’ s on one side of an equation is the same as what’ s on the other.
In Unequal, Eugenia Cheng shows that’ s just part of the story, and the boring part to boot. Mathematics isn’ t only about showing how numbers and symbols are the same. It isn’ t even just about numbers and symbols at all, but a world of shapes, symmetries, logical ideas, and more. And in that world, the boundary between things being equal and unequal is a gray area, or perhaps a rainbow of beautiful, vibrant, subtly nuanced color.
As Unequal shows, once you go over that rainbow, almost everything can be considered equal and unequal at the same time, whether it’ s shapes (seen from the right perspective, a circle is the same as an ellipse), words (synonyms), or people— even numbers! It all depends on what features we care about. And it’ s up to us what we do about it. That’ s because mathematics isn’ t a series of rules, facts, or answers. It’ s an invitation to a more powerful way of thinking.
