In this article I discuss the argument to God from the fact that human beings have a mental life.Footnote ¹ The first part of the article argues simply from the fact of ‘property dualism’, that is the fact that the mental life of humans consists in humans having pure mental events which are not physical events; and the second part argues from the fact of ‘substance dualism’, that is the fact that the mental life of humans is the mental life of a pure mental substance with one essential part (their soul). Both property dualism, and – far more – substance dualism are highly controversial theses, and I give brief arguments in this article in favour of each of them; but for fuller arguments I must refer the reader to other writings of my own and of other philosophers. Those who do not accept dualism of either kind can still regard this article as showing what follows from dualism for theism (the theory that there is a God of the traditional Judaeo-Christian–Islamic kind). Before I come to the details of this argument, I must set it in what I regard as its proper context. I have long defended the view that arguments of any value for the existence of God from the existence of the universe and its most general features are best construed as arguments which increase the probability of (i.e. ‘confirm’) the conclusion that there is a God; and that taken together the evidence reported in these premises makes the conclusion significantly more probable than not. The pattern of argument is the same as that used in science or history. These arguments are arguments to the best explanation, where the best explanation is one that is more probable than not.

There are two different kinds of ways of explaining phenomena. There is inanimate or ‘scientific’ explanation whereby we explain a phenomenon (a B) as caused by initial conditions (an A) in virtue of the operation of a law (a generalization of the form ‘all [or most] A's are followed by B's). And there is ‘personal’ explanation whereby we explain a phenomenon as caused by a person (a substance) in virtue of his power to produce a phenomenon of that kind, the intention to do so, and – in the case of non-basic actions – a belief about how to do so. Persons form their intentions in the light of their moral beliefs about what is most worth doing, and of their desires, which are non-rational inclinations influencing them to do this or that. When they have moral beliefs that two or more incompatible actions are equal best, and desires of equal strength to do each of these actions, they have a (libertarian) free choice of which to do. Similarly, when they have a strongest desire to do an action which – they believe – is less good than some incompatible best action, or (as is the case with God, but not with humans) if there is before them – they believe – an infinite number of incompatible actions, each less good than another action, they have a (libertarian) free choice of which to do. Otherwise they will inevitably do what they most desire to do or believe best to do. An explanation in terms of the action of God is of course a personal explanation; God is not subject to non-rational influences and so will be guided only by his true moral beliefs, that is, by reason. So God will be perfectly good.

The operation of the factors operative in an explanation of one kind may themselves be explained by an explanation of either kind. In either case an explanatory theory is probably true in so far as if it is true, it is probable that the evidence will occur, and it is simple. In the case of theories of narrow scope, such as theories postulating the cause of the behaviour of some particular gene or planet, or of who committed some crime, there is an additional criterion – that the theory fits with our ‘background knowledge’, that is, our wider knowledge of how things work in a wider general field. But in the assessment of a theory of wide scope which seeks to explain an enormous range of phenomena, that criterion drops out; and it must drop out in the assessment of theism, since the latter seeks to explain almost everything observable.

Probabilistic arguments from the general features of the universe to theism must be assessed by how probable theism makes those general features, and whether theism is a simple theory. The various pieces of evidence (the data or phenomena) make it probable that there is a God, in so far as it is more probable that these data would occur if there is a God than if there is no God, and the hypothesis that there is a God is a very simple one. I shall assume for reasons given elsewhere (Swinburne (Reference Swinburne2004), ch. 5, and more recently Swinburne (Reference Swinburne and O'Hear2011)) that God is indeed a very simple being. Cumulative arguments for theism are best presented in the order of the decreasing generality of their premises. We need to begin with the most general datum, that there is a physical universe, and then go on to the datum that it is governed by simple laws, and then to the datum that these laws are such as to lead to the evolution of human bodies; and then to the datum which is the concern of this article – that human beings have a mental life (have sensations, beliefs, desires, occurrent thoughts, and intentions). In each case, I believe, the probability of the datum without a personal being causing it (and the simplest and so most probable such person is a GodFootnote ² ), given only the previous more general datum, is low – e.g. the probability of the laws being such as to lead to the evolution of human bodies, given only that there are simple laws, is very low. For the laws to lead to this evolution, they need to be of one of a very few possible kinds and to be ‘fine-tuned’ versions of that kind (that is, their constants have to lie within an extremely narrow range). If the only causes were physical causes, and so the fundamental laws and the boundary conditions of the universe had no further explanation of a personal kind, probabilistic arguments claim, it would be most improbable that they would be of one of these kinds.

God being perfectly good would try to bring about good things, and, being omnipotent, would succeed in doing so. We humans are especially good things. This is first because have a mental life and enjoy many experiences. Second, this is because we are rational beings, who can come to understand deep truths about the universe. Third, we are agents; it is good to cause things, to be the source of other things, to play a role in forming the universe. We play a considerable role in causing ourselves and others pain or pleasure. Thereby we form our own characters, so that certain sorts of action become natural to us. But fourth, and most importantly, we are good things because – I shall assume here, having argued for it elsewhere (Swinburne (Reference Swinburne2013), chs 4 and 7) – we have libertarian free will. Hence, having also moral beliefs (within limits), we can choose to do what we believe good or what we believe bad, and so we are the ultimate source of our influence for good or ill. We can – by our free choice – make great differences for good or ill to ourselves, each other, and the world. In this we have a kind of goodness which God himself, who can do no evil, does not have; and so he has special reason for bringing about others who have the free choice between doing good or doing evil. Beings who enjoy experiences and are free agents with power to make moral choices need sensations (of pain or pleasure), beliefs (including moral beliefs, and beliefs about how to bring about different events), thoughts (to work out what is good or bad, and how to bring about different effects, and to come to understand much about the nature of the universe), intentions (to initiate our actions), and desires for lesser goods (so that we can choose whether to act on our moral beliefs or to capitulate to less good desires). It is good that beings who have the power to do evil should be beings of finite power who can do to each other and suffer from each other only limited evils. This involves them having the power to some extent to get hold of each other, and to some extent to escape from each other; and that in turn involves each of them having a movable location in some wide sense, a place where they can produce effects directly (by their basic actions), and elsewhere only indirectly (by the effects of their basic actions), and that involves them having bodies in some wide sense.Footnote ³ So it is quite probable that God would bring about (directly or via some process), beings with these properties; and (on the assumption that we have libertarian free will) it is evident that we do have these properties. And so it is probable that he will bring about the necessary conditions for our existence – which are a physical universe, governed by simple laws of nature (which we can understand and so use to bring about effects), laws which cause human bodies (through which we can learn about and operate upon the world), and finally, connected to our bodies, a mental life of the kind just described.

So the strength of the argument from the mental life of human beings depends on just how improbable it is that, given that the laws of nature are such as to lead to the evolution of human bodies, these bodies will be bodies of humans who have a mental life, and on whether having a mental life entails having a soul (a pure mental substance) as one's essential part – if those laws are the ultimate determinants of phenomena and so God does not bring them about. (I am assuming that God is by far the simplest kind of supernatural being, and so that if there is no God, there is no other supernatural being who caused humans to be embodied souls.)

I begin by summarizing the arguments, as they have been presented in the past by myself and others, for the claim that humans having a mental life entails that their bodily events (in effect, brain events) cause and are caused by their pure mental (that is, non-physical events) – that is, the arguments in favour of interactive ‘property dualism’. (For a far fuller and more adequate version of these arguments, see, among other places, Swinburne (Reference Swinburne2013), chs 1, 3, 4, and 7). I understand by an ‘event’ the instantiation of a property (monadic or relational) in a substance (or substances) at a time; the history of the world includes events of two kinds – physical events (including brain events) and mental events. I understand by ‘a physical event’ an event such that anyone can learn about its occurrence as well as anyone else; no one person has privileged access to a physical event. I understand by a ‘mental event’, an event to which its subject (the person in whom the event is instantiated) necessarily has privileged access, that is, a way of knowing about it not available to others, by experiencing it. Among mental events are pure mental events, ones which do not include any physical event. Among these latter are beliefs, occurrent thoughts, intentions, desires, and sensations. These events neither entail nor are entailed by any physical event. Sensations, thoughts, and intentions are occurrences of which necessarily someone who has them at a time must be to some extent conscious at that time of having them. Beliefs and desires by contrast are what I call ‘continuing mental states’; that is, states which continue to exist while we are quite unconscious of them, but are mental because we can become conscious of them if we choose. Pure mental events consist in the instantiation of pure mental properties (such as ‘being appeared to redly’ or ‘having a thought that today is Thursday’) in substances (such as humans) at particular times. A full history of the world would need to include these events as well as physical events. Sensations, thoughts, beliefs, and desires are all caused, many of them directly and many of them indirectly (e.g. via other beliefs) by brain events. The extent to which our intentions are caused is debatable, but clearly – while I shall assume that they are not always totally caused and so we have some free will – brain events have a considerable influence on which intentions we form. Conversely, our intentions (the intentions in our movements, guiding them that is, not intentions for the future) cause our brain events which in turn cause our bodily movements.Footnote ⁴ So if there is, as we reasonably assume, a scientific explanation of these causal relations there must be laws of nature of the form ‘all brain events of kind B₁ cause pure mental events of kind M₁’ and ‘all pure mental events of kind M₂ cause brain events of kind B₂’ (or probabilistic forms of such laws). And we must also suppose that some pure mental events cause other pure mental events. For we often believe propositions because we believe that they are forced upon us by the evidence – that is, the belief that the evidence is so-and-so causes us to hold the belief that such-and-such a hypothesis is true. If we thought that our beliefs never caused other beliefs, we couldn't hold any scientific theory based on evidence, and that would include any theory of mind. So there will also be laws of the form ‘all pure mental events of kind M₁ cause pure mental events of kind M₂’.

Now given whatever fairly simple theory of physics explains the eventual emergence of human bodies, how probable is it that, as well as the laws of that theory, there would be psychological laws of the kind stated above, if scientific laws and objects governed by them are the ultimate causes of all phenomena?

What makes a scientific theory such a theory of mechanics able to explain a diverse set of mechanical phenomena is that the laws of mechanics all deal with the same sort of thing – physical objects, and concern only a few of their properties such as their mass, shape, size, and position, which differ from each other in measurable ways (for example one has twice as much mass as another, or is three times as long as another.) Because the values of these measurable properties are affected only by the values of a few other such properties, we can have a few general laws which relate two or more such measured properties in all objects by a mathematical formula. We do not merely have to say that, when an inelastic object of 100 gm mass and 10 m/sec velocity collides with an inelastic object of 200 gm mass and 5 m/sec velocity, such and such results, with quite unconnected formulae for the results of collisions of innumerable inelastic objects of different masses and velocities. We can have a general formula, a law stating that for every pair of inelastic material objects in collision the quantity of the sum of the mass of the first multiplied by its velocity plus the mass of the second multiplied by its velocity is always conserved. But that can hold only if mass and velocity can be measured on scales – for example, of grams and metres per second. And we can extend mechanics to a general physics including a few more measurable quantities (charge, spin, colour charge etc.) which interact with mechanical quantities, to construct a theory which makes testable predictions.

A psychophysical theory however would need to deal with things of very different kinds. Brain events differ from each other in the chemical elements involved in them (which in turn differ from each other in measurable ways) and in the velocity and direction of the transmission of electric charge. But pure mental events do not have any of these properties. Sensations are not in general analysable in terms of different degrees of a few common elements – being sweet does not differ from being blue in having more or less of some common element. The intentional or – as I shall call them – 'propositional’ events (beliefs, desires etc.), which consist of an attitude to a proposition are what they are and have the influence they do in virtue of their propositional content. While this content can be expressed in a language and so different propositional events do consist of attitudes to things consisting of common elements, there are an enormous number of those elements. While each person's beliefs etc. are expressible in language, it will be a language which – I suggest – has a content and rules differing slightly for each person – we often understand a given word in slightly different ways from each other, and so have slightly different concepts from each other. Propositional events have relations of deductive logic to each other; and (see below) some of those deductive relations determine the identity of the propositional event. The rules of a language which relate the concepts of that language to each other cannot be captured by a few ‘laws of language’ because the deductive relations between sentences and so the propositions which they express are so complicated that it needs all the rules contained in a dictionary and grammar of the language to express them. These rules are independent rules and do not follow from a few more general rules. Consider how few of the words which occur in a dictionary can be defined adequately by other words in the dictionary, and so the same must hold for the concepts which they express; and consider in how many different ways describable by the grammar of the language words can be put together so as to form sentences with different kinds of meaning, and so the same must hold for the propositions which they express.

So a psychophysical theory would consist of very many laws, not derivable from a few more general laws, relating brain events with numerically measurable values of transmission of electric charge in various circuits to conscious (and non-conscious) beliefs, desires, intentions etc. with a content individuated by sentences of a language (varying slightly for each person), and also to sensations. The contents of the mental events do not differ from each other in any numerically measurable way,Footnote ⁵ nor do they have any intrinsic order (except in the respect that some contain others – e.g. a belief that there is a lectern in front of me contains a belief about what a lectern is.)

Could we not at least have an ‘atomic’ theory which would relate particular brain events involving only a few neurons to particular aspects of a conscious state – particular beliefs, occurrent thoughts etc., the content of which was describable by a single sentence (of a given subject's language), in such a way that we could at least predict that a belief with exactly the same content would be formed when the same few neurons fired again in the same sequence at the same rate (if ever that happened)? The problem is that no belief can be held without being sustained by certain other beliefs – for logical reasons; which other beliefs a given belief is thought of as entailing determines in part which belief the latter belief is. My belief that all men are mortal wouldn't be that belief if I also believed that Socrates was an immortal man; and my thought that ‘2 = 1 + 1, and 3 = 2 + 1, and 4 = 3 + 1’ wouldn't be the thought normally expressed by those equations if I denied that it followed from them that ‘2 + 2 = 4’. Now consider two beliefs, whose content is expressed in English by ‘this is square’ and ‘this has four sides’; someone couldn't hold the first belief without holding the second. So these two beliefs cannot always be correlated with different brain events, since in that case a neuroscientist could eliminate the brain event correlated to the latter belief without eliminating the brain event correlated to the former belief. On the other hand these two beliefs cannot always be correlated with the same brain event since someone can have the belief ‘this has four sides’ without having the belief ‘this is square’. To generalize – the belief ‘this has four sides’ must be correlated with each of the different brain events which are correlated with any belief which couldn't be held without the believer believing that it entails ‘this has four sides’. It follows that any given propositional event is correlated with many different brain events. That leads to the view that propositional events only occur as part of a large mental state, including many other mental events, and it is this large mental state which is correlated with a large brain state without there being correlations between separate parts of the mental and brain states.

So psychophysical laws would consist of an enormous number of separate laws, not derivable from a few more general laws, relating large brain events with numerically measurable values of transmission of electric charge in various circuits, to large conscious (and non-conscious) states consisting of beliefs, desires, intentions etc. with a content individuated by sentences of a language (varying slightly for each person), and also sensations, all of different strengths. To suppose that a theory of physics with all this added is the ultimate explanation of the data of consciousness is to postulate a very un-simple and so a priori very improbable ultimate theory . Could not God have caused us to exist as embodied beings without the laws connecting our brains and our mental life being so complicated? Not, I suggest, if we are to have rich mental lives, each a bit different from each other, and able to reason about the nature of the world, and influence each others' mental lives for good or ill. Hence it is probable that God would bring about psychophysical laws of the kind we have, and hence their existence greatly increases the probability of the existence of God.

I should add that this point is unaffected by the theory of Evolution by natural selection. No doubt natural selection selects organisms inclined to have beliefs, desires etc. which will help them to survive, and that means true beliefs and useful desires, and thoughts and sensations conducive to such beliefs and desires. But it can only do this by selecting organisms which have brain events which normally produce in appropriate circumstances the beliefs, desires etc. which enable those organisms to survive; and it can only do that by selecting organisms whose genetic structure causes them to have the relevant brain events. But all this depends on the operation of the innumerable highly complicated psychophysical laws whereby brain events cause and are caused by mental events – which laws would exist whether or not evolution had ever taken place.

So much for the argument from mental events, that is in effect from humans being conscious or having the capacity to be conscious in various ways. But I now give very brief arguments in favour of ‘substance dualism’, that the mental life of humans is the mental life of a pure mental substance with one essential part – their soul. (For a far fuller and more adequate version of these arguments, see, among other places, Swinburne (Reference Swinburne2013), chs 1 and 6.) Our mental life depends on our brains, and some of our memories and character depend on events in different halves of the brain. In the half-brain transplant thought experiment where half of my brain is taken out of my skull and put into the skull of my identical twin, replacing half of his brain, it is logically possible that the resulting person is me and logically possible that it is not me – even if we add to the description every detail about the physical and pure mental properties of the resulting person.

Some philosophers say that while this may be logically possible, in the sense of not entailing a contradiction, it is not ‘metaphysically’ possible. A proposition may be logically possible without being metaphysically possible (understanding by ‘metaphysically possible’ such as would be true if the world were different in some (logically) possible way) if we do not pick out the substances or properties referred to by what I call ‘informative [rigid] designators’. For a rigid designator of a thing to be an informative designator it must be the case that anyone who knows what the word means (that is, has the linguistic knowledge of how to use it) knows a set of conditions necessary and sufficient (in any possible world) for a thing to be that thing (whether or not he can state those conditions in words.) To ‘know’ these conditions for the application of a designator – as I am understanding this expression – just is to be able (when favourably positioned, with faculties in working order, and not subject to illusion) to recognize where the informative designator (or, if it is defined in words, the words by which it is defined) applies and where it does not, and to be able to make simple inferences to and from its application. Thus ‘water’ as used in the eighteenth century was an uninformative designator, whereas ‘H₂O’ is an informative designator. ‘Water’ as used in the eighteenth century was an uninformative designator, because the rules for its use were that it applied to any stuff which has the same underlying essence as the stuff in our rivers and seas. As speakers did not know what that essence was, they could not know whether ‘water’ applied to some substance other than the stuff in our rivers and seas. ‘H₂O’ however is an informative designator since it is defined by words such as ‘mass’ and ‘10⁻¹’, the necessary and sufficient conditions for applying which we know. A logically possible proposition is metaphysically possible iff it remains logically possible when we substitute co-referring informative designators for uninformative ones. When we know fully what we are referring to- as we do when we use an informative designator- we are in a position to know what could be true of it if the world were different in some (logically) possible way, or could not be true of it, however different the world was in any (logically)'possible way.

Contrary to objectors, I argue that ‘I’ or ‘Richard Swinburne’ as used by me are informative designators. If I know how to use these words, I can't be mistaken about when to apply them – as long as I am favourably positioned, with faculties in working order, and not subject to illusion; and when I am considering applying these words to a person in virtue of his being the subject of a present experience, no mistake at all is possible. I am in Shoemaker's (Reference Shoemaker1970) phrase ‘immune to error though misidentification.’ I cannot know how to use the word ‘I’, recognize that someone is having some conscious event (e.g. some pain), and still wonder whether it is I or someone else who is having that event, in the way that an eighteenth century speaker could know how to use the word ‘water’ and yet not know whether some substance other than the liquid in our rivers and seas was or was not water. Hence in the half-brain transplant experiment if it is logically possible that the resulting person is me and logically possible that it is not me – even if we add to the description every detail about the physical and pure mental properties of the resulting person, it is metaphysically possible that the resulting person is me and metaphysically possible that it is not me.

But by another (to my mind) plausible principle, which I call the Principle of the Identity of Composites, there cannot (logically) be two things which have all the same parts, having all the same properties (including relations, and past-related properties) . For example, given a certain car standing in the car lot with certain parts having properties, including such past-related properties as being part of a car made in a certain factory from such-and-such matter which travelled just those roads etc. etc., there couldn't be instead of it a different car which had all the same parts having all the same properties. So if it is metaphysically possible that there be a certain person who has all the same physical parts and all the same properties, mental and physical, as me, and yet is not me – there must be another non-physical part of me which makes me me, which is naturally called my soul. And since I can know this merely in virtue of knowing to what my use of the word ‘I’ refers, other people can know the same about themselves. What applies to me, applies to all other human persons.

So if science is to explain the existence of humans, it must include laws of the form ‘all brain events of a certain kind cause the existence of a soul in interaction with them’, and laws determining which brain events would keep the same soul in existence. And since I exist only in so far as I have a mental life, the laws governing which brain events produce sensations, beliefs etc. must be rephrased as laws governing which brain events cause the connected soul to have sensations, beliefs etc. of various kinds. That has the consequence that the psychophysical addition to modern physics makes the resulting science an even more complicated science than it would be otherwise.

But finally such laws would not explain the (to each ‘me’) all important datum that the development of the brain which is currently mine did not merely cause the existence of a soul; it caused the existence of my soul, the essential part of me. Human beings, and so our souls have a ‘thisness’ which makes us who they are. For our distinguishing physical and mental properties are neither necessary nor sufficient to make us who we are. We can see this by reflecting on the fact that the world could have been different if you (and so your soul) had had my body connected with all the mental and physical properties which I have at each time, and I (and so my soul) had had your body connected with all such properties which you have at each time – ‘could’ in the sense of being ‘logically possible’ and so, given that the use of ‘I’ by each of us is that of an informative designator, ‘metaphysically possible’. Laws of the kind so far suggested could have produced any of innumerable different souls, and so innumerable different persons. So how about laws mentioning individuals? Maybe there's a law of the form ‘all brain events of a certain kind cause the emergence of the soul of Richard Swinburne’. But if the psychophysical laws were of that kind, then brain events of the kind that caused the emergence of me, would, if brain events of the same kind as caused the emergence of me on this planet occurred also on a distant planet, also cause the emergence of me – and that couldn't happen because the person on the distant planet, having no access at all to the mental life which is mine, couldn't be me. So maybe the laws are of a kind that couldn't cause the existence of an already existing soul – e.g. ‘all brain events of a certain kind cause the emergence of my soul, if that soul is not already functioning somewhere in the universe.’ Such a law would make it possible to engineer reincarnation. But if there is a law of this kind governing the evolution of me, there would have to be a separate unconnected law for each human alive now – at least 6 billion separate fundamental laws! This, together with all the separate laws determining which mental events are produced in a connected soul, would make science so complicated as to be a priori extremely improbable and of course quite unverifiable – since only laws with repeatable consequences can be verified by predictions. ‘Emergent Dualism’ – to my mind implausibly- seems to deny that humans have ‘thisness’.

The alternative and to my mind more satisfactory scientific account of what happens would be that there is a law determining that certain brain events cause the emergence of a soul, but that it is a chance matter whose soul it is which results. Is this a problem? After all, Quantum Theory has familiarized us with the idea of indeterministic processes operating in nature. The difference however is that that a quantum process is a repeatable process: an event of this kind is followed with a certain fixed probability by an event of that kind. But given that fundamental particles (and so the larger physical objects composed of them) do not have thisness, as philosophers of physics generally suppose that they do not,Footnote ⁶ what cannot fit readily into the scientific scheme is indeterministic non-repeatable causality (of causing new entities not specifiable in advance). But this is what – given a psychophysical theory – causing the emergence of me would involve. So again the scientific account has to incorporate into modern physics a kind of causation otherwise unknown; and so again yet more complexity, which makes it yet more improbable that a psychophysical theory provides an ultimate explanation of its phenomena.

Can theism do any better? Before answering this question directly, I draw attention to a feature of my definition of an event as mental iff the subject necessarily has privileged access to it by experiencing it. That leaves open the possibility that some other person might necessarily have privileged access to it by some other route. That person would clearly have to be a very different kind of person from ordinary humans; but since there does not seem to be any internal contradiction in supposing this, an omnipotent God could have that different sort of privileged access, provided by his unique relation to all conscious beings of being their creator (and sustainer). If he has this access, he will know not merely which mental events you and I are having, but also who we are – he will be able to refer to each of us by an informative designator. Knowing the essence of each of us, he will therefore know the difference between creating me and creating someone else. But as souls do not differ from each other in virtue of having different necessary properties, and since before they are created they cannot have any contingent properties (‘hard’ properties, that is, properties which belong to them in virtue of how things are with them at that time), there will be no property of either of us which could provide God with a reason for creating me rather than someone else, connected to a particular body; and God is not subject to non-rational desires in favour of one choice rather than the other. But this is a familiar situation for all rational beings, when faced with equally good incompatible alternatives, and subject to no non-rational desires. In such a situation inevitably we have to make a ‘mental toss’ which alternative to bring about. Hence we would expect God, a person acting solely on reason, to do the same when be faced with this situation. It doesn't complicate the hypothesis of theism to suppose that this happens, whereas to incorporate the production of souls having ‘thisness’ within science does complicate vastly the kind of scientific causation which operates. The biblical stories picture God as choosing persons and races, to do certain jobs, without choosing them because of their suitability to do those jobs. Deuteronomy describes Moses as saying to the Israelites: ‘The Lord your God has chosen you out of all the peoples on earth to be his people . . . it was not because you were more numerous than any other people that the Lord set his heart on you and chose you – for you were the fewest of all peoples.'Footnote ⁷ It is not implausible to suppose that a totally rational God would choose among the infinite number of possible souls those whom he will bring into existence by a similar arbitrary decision.. But to suppose that psychophysical laws determine who is to exist would involve immensely complicated and so a priori immensely improbable processes of a kind totally foreign to deterministic or indeterministic science. So for all these reasons the phenomenon of human mental life greatly increases the probability of the existence of God.