Discussions of space and time often cite the philosopher Immanuel Kant, who argued that these concepts are a priori categories that cannot be studied directly. “Space is nothing but the form of all appearances of outer sense . . . [that] can be given prior to all actual perceptions, and so exist in the mind a priori, and . . . can contain, prior to all experience, principles which determine the relations of these objects.”4 Space and time are thus the axioms of the universe, orthogonal to each other and independent from everything else.
