# Sideways music NED MARKOSIAN **Opening (not a real abstract):** There is a popular theory in the metaphysics of time according to which time is one of four similar dimensions that make up a single manifold, which is appropriately called spacetime. Some of the ways in which time is supposed to be similar to the dimensions of space, according to this theory, include the following: (i) there is no intrinsic direction to time; (ii) physical objects are extended in time in virtue of having different temporal parts in different regions of time; (iii) the so-called ‘A-properties’ (such as being present, being past and being future) are not to be included in accurate descriptions of fundamental reality;1 (iv) there is no such thing as the passage of time; (v) there are no ontological distinctions between past, present and future. I will refer to this popular theory as the Spacetime Thesis. Here is a formulation of the view.2