Time isn’t just another dimension, argues Tim Maudlin. To make his case, he’s had to reinvent geometry.
Physicists and philosophers seem to like nothing more than telling us that everything we thought about the world is wrong. They take a peculiar pleasure in exposing common sense as nonsense. But Tim Maudlin thinks our direct impressions of the world are a better guide to reality than we have been led to believe.
Not that he thinks they always are. Maudlin, who is a professor at New York University and one of the world’s leading philosophers of physics, made his name studying the strange behavior of “entangled” quantum particles, which display behavior that is as counterintuitive as can be; if anything, he thinks physicists have downplayed how transformative entanglement is. At the same time, though, he thinks physicists can be too hasty to claim that our conventional views are misguided, especially when it comes to the nature of time.
He defends a homey and unfashionable view of time. It has a built-in arrow. It is fundamental rather than derived from some deeper reality. Change is real, as opposed to an illusion or an artifact of perspective. The laws of physics act within time to generate each moment. Mixing mathematics, physics and philosophy, Maudlin bats away the reasons that scientists and philosophers commonly give for denying this folk wisdom.
The mathematical arguments are the target of his current project, the second volume of New Foundations for Physical Geometry (the first appeared in 2014). Modern physics, he argues, conceptualizes time in essentially the same way as space. Space, as we commonly understand it, has no innate direction — it is isotropic. When we apply spatial intuitions to time, we unwittingly assume that time has no intrinsic direction, either. New Foundations rethinks topology in a way that allows for a clearer distinction between time and space. Conventionally, topology — the first level of geometrical structure — is defined using open sets, which describe the neighborhood of a point in space or time. “Open” means a region has no sharp edge; every point in the set is surrounded by other points in the same set.
Maudlin proposes instead to base topology on lines.
Read it all here.
Related reading: Meauring Time with the Clepsydra; The Clepsammia; Theories of Time and Eternity; Change and Constancy