A cosmological argument is an argument to the existence of God from the existence of some finite object or, more specifically, a complex physical universe. There have been many versions of the cosmological argument given over the past two-and-a-half millennia; the most quoted are the second and third of Aquinas’s five ways to show the existence of God. However, Aquinas’s ‘five ways’, or rather the first four of his five ways, seem to me to be one of his least successful pieces of philosophy. In my view the two most persuasive and interesting versions of the cosmological argument are that given by Leibniz in his paper On the Ultimate Origination of Things, and that given by his contemporary Samuel Clarke in his Boyle Lectures for 1704 and published under the title A Demonstration of the Being and Attributes to God. The former seems to be the argument criticized by Kant in the Critique of Pure Reason and the latter the argument criticized by Hume in the Dialogues.

The starting points of cosmological arguments are evident facets of experience. There is no doubt about the truth of statements that report that they hold. It seems to me equally evident that no argument from any of such starting points to the existence of God is deductively valid. For, if an argument from, for example, the existence of a complex physical universe to the existence of God were deductively valid, then it would be incoherent to assert that a complex physical universe exists and God does not exist. There would be a hidden contradiction buried in such co-assertions. Now, the only way to prove a proposition to be incoherent is to deduce from it an obviously incoherent proposition (for example, a self-contradictory proposition),but, notoriously, attempts to derive obviously incoherent propositions from such co-assertions have failed through the commission of some elementary logical error. Furthermore, it seems easy enough to spell out in an obviously coherent way one way in which such a co-assertion would be true. There would be a complex physical universe and no God, if there had always been matter rearranging itself in various combinations, and the only persons had been embodied persons; if there never was a person who knew everything, or could do everything, etc. Atheism does seem to be a supposition consistent with the existence of a complex physical universe, such as our universe. Of course things may not be as they seem, but, in the absence of any worthwhile argument to the contrary known to me, I shall assume that the non-existence of God is logically compatible with the existence of the universe, and so that the cosmological argument is not a valid, and so not a good, deductive argument. Our primary concern is however to investigate whether it is a good C-inductive or P-inductive argument, and just how much force it has.

There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that "remembered" a wholly unreal past. There is no logically necessary connection between events at different times; therefore nothing that is happening now or will happen in the future can disprove the hypothesis that the world began five minutes ago.

If all the evidence in the universe turned in favour of creationism, I would be the first to admit it, and I would immediately change my mind. As things stand, however, all available evidence (and there is a vast amount of it) favours evolution.

Creation science argues that there are only two views, special creationism and evolution; thus, arguments against evolution are arguments in favor of creationism. Literature supporting creation science is based on alleged examples of evidence against evolution, which are considered not only proof against evolution but also positive evidence for creationism. Understandably, there is nothing in the creation science canon providing a positive scientific case for the sudden emergence of the universe in its present form at one time, let alone for its specific doctrines a six-thousand-year-old Earth and universe, the occurrence of a worldwide flood responsible for the fossil record and geological features such as the Grand Canyon, and the impossibility of evolution except within sharp limits.

I do not propose to argue the case for evolution, which I regard as being quite as well proven as most other historical facts, but to discuss its possible causes, which are certainly debatable.

Many modern philosophers claim that probability is relation between an hypothesis and the evidence for it.

... the Big Bang theory is the accepted theory of cosmology. You never prove anything completely, but it’s the accepted theory of cosmology. And we continue on, in my group, we continue on with balloon observations, and then there’s the and now we’re getting the ready with the , who is sponsoring that. So there’s a whole sequence. What it was, was that was the opening shot and saying OK, there’s some gold to be discovered in the hills, go looking for it.

It is remarkable that observation of the faint agglomerations of stars known as galaxies leads us, very directly and cleanly, to the conclusion that we live in a Universe of finite and determinable age. A century ago, no one could have offered even an approximate age for the Universe. For an upper bound, most nonreligious scientists would probably have said “forever.” For a lower bound, all they had was the age of the Earth.

One finds in this subject a kind of demonstration which does not carry with it so high a degree of certainty as that employed in geometry; and which differs distinctly from the method employed by geometers in that they prove their propositions by well-established and incontrovertible principles, while here principles are tested by inferences which are derivable from them. The nature of the subject permits of no other treatment. It is possible, however, in this way to establish a probability which is little short of certainty. This is the case when the consequences of the assumed principles are in perfect accord with the observed phenomena, and especially when these verifications are numerous; but above all when one employs the hypothesis to predict new phenomena and finds his expectations realized.

I am not very impressed with theological arguments whatever they may be used to support. Such arguments have often been found unsatisfactory in the past. In the time of Galileo it was argued that the texts, "And the sun stood still... and hasted not to go down about a whole day" (Joshua x. 13) and "He laid the foundations of the earth, that it should not move at any time" (Psalm cv. 5) were an adequate refutation of the Copernican theory.

Analogy would lead us to conclude that the combinations of the primordial matter, forming our so-called elements, are as universal or as liable to take place everywhere as are the laws of gravitation and centrifugal force. We must therefore presume that the gases, the metals, the earths, and other simple substances, (besides whatever more of which we have no acquaintance,) exist or are liable to come into existence under proper conditions, as well in the astral system, which is thirty five thousand times more distant than Sirius, as within the bounds of our own solar system or our own globe.

Reason nevertheless prevails in world history.

There is incontrovertible evidence from lead-isotopic data that meteorites are approximately 4.55 ± 0.02 Ga. We can presume, as the evidence indicates, that the solid bodies of the Solar System formed nearly simultaneously, and conclude that the Pb-Pb age of meteorites also represents the age of Earth.