Swinburne introduces his approach. He is not trying to come to an indubitable conclusion; his goal is a probabilistic one based upon confirmation theory. So, of the fourteen chapters, the first four describe inductive arguments, the nature of explanation, justification of explanation, and complete explanation. The author first aims to show the need to take the arguments for God’s existence together:
One unfortunate feature of recent philosophy of religion has been a tendency to treat arguments for the existence of God in isolation from each other…But clearly the arguments may back each other up or alternatively weaken each other, and we need to consider whether or not they do.1Swinburne rejects a piecemeal criticism of arguments for God:
Sometimes, however, philosophers consider the arguments for the existence of God in isolation from each other, reasoning as follows: the cosmological argument does not prove the conclusion, the teleological argument does not prove the conclusion, etc. etc., therefore the arguments do not prove the conclusion. But this ‘divide and rule’ technique with the arguments is inadmissible.2Again, the author emphasizes the need to assess the weight of all the evidence:
The crucial issue, however, is whether all the arguments taken together make it probable that God exists, whether the balance of all the relevant evidence favours the claim of theism or not…we ought to act on a hypothesis in so far as it is rendered probable by the total evidence available to us – all we know about the world, not just some limited piece of knowledge.3Swinburne presents an analogy of a scientific theory to explain the need to assess the arguments together: “Thus each of the various pieces of evidence that are cited as evidence in favour of the General Theory of Relativity do not by themselves make it very probable, but together they do give it quite a degree of probability.”4 He says that the probability of a theory being true rests partially in its explanatory power: “…for a theory to have great explanatory power, the phenomena that it predicts must be such that but for it they would not otherwise be expected.”5
As Swinburne sets the stage for his cumulative assessment, he also shows that an explanation does not itself need to be explained before it can be a satisfactory explanation. He thus puts the “who designed the designer?” objection in its place:
Now a full explanation really does by itself explain why something happened. It does so quite independently of whether or not there is an explanation of how any states it cites came to be…or why any reasons that it cites operate… To suppose otherwise is to commit a fallacy that we may call ‘the completist fallacy’. Clearly it is a fallacy. For if it were really the case that F could not explain E unless there is an explanation of F, nothing in the universe could be explained, unless there were explanations of such things as the origin of our galaxy – which is absurd.6After his preliminary exposition of his inductive approach (which includes a treatment of Bayes’ theorem) Swinburne begins with what he calls the inherent probability of theism. This hinges on the idea that theism is, in itself, a very simple hypothesis: “Theism postulates God as a person with intentions, beliefs, and basic powers, but ones of a very simple kind, so simple that it postulates the simplest kind of person that there could be.”7 He develops this idea in much depth, as simplicity is the major determinant of intrinsic probability: “So in postulating a person with infinite power the theist is postulating a person with the simplest kind of power possible.”8 Swinburne explains that unlimited power is simpler to posit than power that is limited to some finite degree:
To postulate a G of very great but finite power, much but not all knowledge, etc., would raise the inevitable questions of why he has just that amount of power and knowledge, and what stops him from having more, questions that do not arise with the postulation of God.9Before moving on to the classical arguments for theism, Swinburne reminds the reader that his assessment is to show the greater explanatory power of theism: “how much more likely does the existence of God make the occurrence of those phenomena than it would be if we do not assume the existence of God.”10 It is at this point that the book shifts into exploring one or two major arguments for the existence of God per chapter. These include: the cosmological argument, teleological arguments, arguments from consciousness and morality, the argument from providence, the problem of evil (which counts against the theistic hypothesis), arguments from history and miracles, and the argument from religious experience.
In dealing with the cosmological arguments, the author shows that either the universe is the “stopping point” or God is the “stopping point.” As for design arguments, Swinburne treats them “not as an argument from analogy (the way typical of the eighteenth century) but in the way in which other arguments are treated in this book, as an argument from evidence that it would be probable would occur if theism is true, but not otherwise.”11 Noted here is the fact that Swinburne shows the greater probability of theism given evidence for design even though Swinburne seems to concede macroevolutionary theory: “So our question becomes – why are there not just any laws of nature, but laws of a particular kind such that together with the initial matter-energy at the time of the ‘Big Bang’ would lead to the evolution of human bodies.”12
Swinburne includes an evaluation of evidence from the fine-tuning of the universe for life, which entails 15 or so pages. He criticizes multiverse theory:
…it is the height of irrationality to postulate an infinite number of universes never causally connected with each other, merely to avoid the hypothesis of theism. Given that simplicity makes for prior probability, and a theory is simpler the fewer entities it postulates, it is far simpler to postulate one God than an infinite number of universes, each differing from each other in accord with a regular formula, uncaused by anything else.13Topping of his design argument, the author also includes the argument from beauty. His two chapters dealing with consciousness, morality, and providence follow. Within these chapters the reader will find amazing philosophical work. At this point Swinburne again concludes that each one of these arguments are more probable if theism is true, while emphasizing their overall cumulative effect: “as we consider more and more phenomena, the probability that they will occur if there is no God gets less and less.”14
Swinburne’s assessment is not all positive. Chapter eleven’s presentation of the issue of evil is sober and honest. Common defenses against evil are presented, but the author also shows where they may fall short. Chapter twelve then explores the argument from history and miracles: “if there is a God, there exists a being with power to set aside the laws of nature that he normally sustains”15 Swinburne presents four types of evidence that can be furnished to support miracles. Chapter thirteen is in a similar vein, dealing with the argument from religious experience. Here the author explores five kinds of religious experience and determines how one can determine the veracity of such claims.
The book ends with a final chapter weighing the probabilities. Swinburne’s conclusion: “On our total evidence theism is more probable than not.”16 Whether one agrees or disagrees with Swinburne’s conclusions or methods, this is a praiseworthy book from a strictly philosophical point of view. Nevertheless, The Existence of God will prove to be both a challenging and rewarding book for the reader.