DEFINITION OF SPACE AND TIME 77 It was first shown by Minkowski in 1908 that these measurements of time intervals and spatial separation between a given pair of events could be combined into a single number ds which would be invariant for all iner-tial observers. He gave the formula ds2^ cdt^dl rs0302 where c is the speed of light, dt is the time interval and dl is the distance between the events. If we select appropriate units of length and time so that the speed of light in vacuum becomes unity, and if we remember the theorem of Pythagoras for the distance between two points we can express the invariant by the formula ds^^:== OOdt dx ^z ^ ^ls ^peression is called the metric and the set of all events with this structure is called the space-time of STR. Not the order of pluses and minuses on the right hand side of this formula of the metric. This order of signs is called the signature of the metric. The signature of the space-time ofSRT, as well as the space-time of general relativity is plus, minus, minus, minus. Any space having a metric with this signature is said to have a Loreniz metric. The space-time of relativity is a four demensional space with a Lorentz metric. MISNER'S ARGUMENT ON SIGNATURE OF SPACE-TIME Though Misner stands by the big bang model of the universe and believes that the universe came into being in an act of creation, he does not want to push the idea of God as someone who merely lit the fuse to get the whole thing going. That would be too simplistic an argument. Misner sees God in the context of what he calls the distinctness of existence [14] from conceptualization. To make his idea clear I quote : "In order to recognise that our Universe, at least to the extent that it is currently intelligible, has a design that is distinct from its existence, it may be useful to consider other designs for which we cannot assert a comparable existence". Misner then refers to a figure appearing in the text where a two dimensional Minkowski space is exhibited. Because of the special way intervals are calconger segments. Misner makes this a ground for the following line of argument: 'The mathematician has no difficulty designing a two dimensional Minkowski space-time, but the printer finds it impossible to make or buy one to bind into this volume.... Because of our inability to bestow existence on this simple conception. Fig 3 had to be drawn as a two dimensional Euclidean space and supplemented by a pony explaining how it was to be translated conceptually into a two dimensional Minkowski space-time. Were existence not distinct from conceptualization, but perhaps simpler, insoluble problem is the request to produce (not necessarily create from nothing and nowhere) a geometrical region with a hyper Minkowski Pythagorean relationship ds2 == dt2 + dx2 — dy2 — dz2 of signature plus, plus, minus, minus to replace the metre which governs the space-time of normal laboratories and bookshelves. To say that one of these formulas is a correct physical law and the other incorrect is to focus attention on a