 Both versions of the argument ask us to consider the cosmos in its present state. Is the world as we know it something that necessarily exists? At least with respect to ourselves, the planet, the solar system and the galaxy, it appears not. With respect to these items in the cosmos, it makes sense to ask why they exist rather than not. In relation to scientific accounts of the natural world, such enquiries into causes make abundant sense and are perhaps even essential presuppositions of the natural sciences. Some proponents of the argument contend that we know a priori that if something exists there is a reason for its existence. So, why does the cosmos exist? Arguably, if explanations of the contingent existence of the cosmos (or states of the cosmos) are only in terms of other contingent things (earlier states of the cosmos, say), then a full cosmic explanation will never be attained. However, if there is at least one necessarily (non-contingent) being causally responsible for the cosmos, the cosmos does have an explanation. At this point the two versions of the argument divide.