For many contemporary atheists a significant justification for their belief is the claim that there is no evidence for the existence of God.Footnote 1 They compare the lack of evidence for God to the lack of evidence for such beings as leprechauns and goblins. And they point out that for belief in the non-existence of alleged entities such as these it is not necessary to prove the negative, which would not be possible, but it is sufficient to show that after due scrutiny there is a lack of affirmative evidence. We reasonably believe, they argue, that there are no such beings as leprechauns and goblins not because we have found proof that they do not exist but simply because we have found no evidence to suggest that they do exist. And similarly in the case of the existence of God.
My response is to wonder what is really meant by the term ‘evidence’ and to what extent it throws light on the problem of the existence of God. First, an attempt to analyse ‘evidence’:
a) Tracks and droppings identified by zoological experts count as evidence that there is a leopard in the forest. Evidence of this sort is capable of verification when, say, a leopard is captured in that vicinity.
b) Bones and teeth are considered to be evidence of the former existence of a stegosaurus. In this case of evidence there is no possibility of it being verified in the same way as in category a). However, in common with category a), it is at least verifiable in principle for the stegosaurus was a physical object capable of being perceived; it is conceivable that a human transported in time and space might perceive it.
c) A leopard and a stegosaurus are both physical objects capable of being perceived and both, in addition, occupy a particular location in the universe. In the case of black holes we can hardly call them physical objects in the same sense but we can say of them that they occupy a particular location in the universe. One black hole might be a certain distance from another black hole or from a particular galaxy. But there is a critical distinction between the evidential status of a black hole and that of a leopard or a stegosaurus. For unlike them a black hole cannot be perceived directly in either sense, not directly like the leopard and not conceivably like the stegosaurus. And the reason for this distinction is that a black hole draws into itself whatever surrounds it within a certain range but emits nothing from itself not even light. Since it emits no light, then in principle it cannot be seen. We can conceive of human beings transported back in time and space to see a dinosaur: we cannot conceive of human beings being transported back or forward to any point in time or in space to see a black hole. The existence of a black hole, therefore, is inferred from its effect on nearby astronomical bodies; it is not, for reasons stated above, an object of actual or potential observation.
We might call these three categories of evidence a) of what is directly perceptible b) of what is conceivably perceptible and c) of what is inferred but imperceptible.
What then of God in this context? Is there evidence of the existence of God? Is an evidence-based approach appropriate here? And, if so, are the categories outlined above helpful in resolving the problem?
Categories a), b) and c), as mentioned above, are types of evidence to show the existence of entities that are located within the physical universe. God, however, as the term is usually understood, is not one object among other objects in the physical universe but, according to the received definition, the creator or ground of the universe. I do not intend to address here the definition of God as a philosophical problem in its own right but, leaving that aside, to explore what bearing this special position of God has on the question of evidence.
In the history of the philosophy of religion there have been many attempts to offer observations of the way the universe is constituted as evidence for the existence of God. Indeed, such claims are at the heart of the teleological or design argument. Examples often presented to make this case are: the orderliness, symmetry and purposefulness of parts of the natural world. The arguments are likely to be closest in form to category c) above, that is, to involve an inference from empirical evidence of what is in principle imperceptible.
But there is a particular difficulty in an attempt to justify the claim that God exists by virtue of evidence. Let me take one example of a piece of evidence that might be brought in to support the argument for design. The symmetry of a snowflake is held more likely to be the product of a designer than to be a random outcome of purposeless nature. But think what step has been taken implicit in the presentation of that piece of evidence. One item has been picked out from the physical world as possessing the significant quality of symmetry and, of course, by virtue of that selection other items in the physical world (like stones and clouds which lack obvious symmetry) have been ignored. In category a) the zoologist focuses on the tracks and droppings of the leopard and takes no interest in the surrounding treetops and lianas since they are irrelevant to his search. Indeed, whenever we look for evidence it is usual to acknowledge that certain items are significant but many other items are not. This distinction holds true whether we are concerned with evidence as understood in a court case or in historical or scientific investigations. We sift, we differentiate, we are accustomed to say that whereas this item in particular counts as evidence that item has no bearing and should rightly be left out of consideration.
Surely, if God is defined in the terms of the teleological argument as the designer of the universe, then the universe in its entirety must count as evidence not certain items selected from the universe? Not just snowflakes, petals, the human eye and the wings of birds but sandstorms, tundra, floods, earthquakes, tsunamis and so on. (I shall resist for reasons of brevity a digression into the problem of evil that this notion invites.) It may be objected that God has made the universe in such a way that certain items are meant to stand out as clear evidence of design (as ‘trademarks’, to borrow a term from Descartes) whereas other items are equally the products of design and evidence of a designer but are meant to be less conspicuously so. But if this move is made, then the effectiveness of evidence as a useful term in the discussion will be undermined. For now any detail of the universe is allowed to count as evidence, the asymmetrical as much as the symmetrical, the disorderly as much as the orderly and the purposeless as much as the purposeful. When all possible observations count as evidence and none can count as counter evidence, then the term ‘evidence’ loses its force.
Ironically, the case for God would now be open to the sort of criticism made of evolutionary theory. We are told that the giraffe's neck, the snake's venom, the bird's curved beak are evidence of the process of evolution through mutation and natural selection. When we ask why other animals have not developed these useful features, we are told that, in a way that is still consistent with evolutionary theory, there was a lack of environmental pressure conducive to such development. Now, both evolutionary development and the absence of evolutionary development are being regarded as evidence in support of evolutionary theory. But once such an extension has been allowed, it is difficult to conceive of any observation of the natural world which would be accepted as evidence counter to evolutionary theory. Species change and species constancy are equally consistent with the overarching theory. When all observations are classed as positive evidence, we have stopped using the notion of evidence in any meaningful way.
John WisdomFootnote 2 addressed the question of evidence for the existence of God by the analogy of the garden. Two people, a theist and an atheist, are looking at a garden. To the theist, whose eye is drawn to the flowers rather than to the weeds, the garden is evidence of the existence of a gardener: to the atheist, whose eye is drawn to the weeds rather than to the flowers, the garden does not require a gardener. The important point here is that both theist and atheist are looking at the same piece of land, have the same visual input, are presented with the same empirical data. The difference between them, then, is not a difference in the evidence but rather in the way the same evidence is interpreted.
Anthony FlewFootnote 3 developed Wisdom's garden analogy in the following way. He supposed that the theist and the atheist kept a vigil at the garden on the lookout for any gardener who might appear. No gardener is seen. Next, a fence is put round the garden and there are dogs patrolling it. The vigil continues but still no gardener is seen. To maintain the belief that there is a gardener the defence is put forward to the effect that the gardener is invisible or even completely inaccessible to human senses. To Flew, a gardener redefined in these terms, invisible etc., is effectively no different from no gardener at all.
Flew thinks that theists make analogous moves to maintain their beliefs. In the face either of a lack of evidence or of counter evidence they resort to a redefinition of God rather than abandon their beliefs. God, like the gardener, becomes invisible, imperceptible, inaccessible by empirical means. There is no evidence that they will admit that undermines their position. Flew concludes that theists hold a belief that is unfalsifiable. Does there exist a leopard, a stegosaurus, a black hole? These are questions that can be settled one way or another by an examination of the evidence. Show evidence and there are grounds for belief: fail to show evidence and the belief is unsustainable. By contrast, the belief of the theist, Flew argues, cannot be falsified no matter what evidence is presented to counter it.
We can explore this point further in Flew's general direction. Suppose the theist has pointed to the features of the universe that contribute to human wellbeing as evidence of the existence of God. We next imagine a scenario in which the number of people and animals who suffer is greatly increased and that the intensity of suffering is greatly magnified. Does the theist now accept that if this were the true state of the world it would count as evidence against the existence of God? Probably not. The theist is more likely to advance the case that while the symmetry in the universe giving delight to humans is evidence of the existence of God in his role of benign provider, the suffering in the universe which is a test of faith (see, for example, the experience of Job in the Old Testament) is equally cogent evidence of God in a sterner capacity. Again, and this is essentially Flew's point, if everything in the universe, in human experience is evidence of God and nothing can be admitted to contradict it, then the notion of evidence has ceased to do useful work. An unfalsifiable belief, to Flew, is not a meaningful one.
For this reason I find the evidence-based approach to the philosophical problem of God to be unsatisfactory. The following quotation from Wittgenstein's Tractatus (admittedly, taken out of context) comes to mind –
‘not how the world is but that it is is the mystical’
– which in the context of this discussion draws attention to the distinction between the ‘how’, the way the universe is configured, the sort of evidence that might be brought into a teleological argument and the ‘that’, the fact that there is any type of universe at all.
The attack mounted by Flew is, I suggest, based on a misapprehension about the nature of the belief that God exists. Not all questions of belief are settled by evidence and it may be that this is one of them. Indeed, some of the most basic of our beliefs are in this category. As an example, consider the problem of our knowledge of an external world, the difficulty of showing convincingly whether or not there exists a domain of physical objects independent of our experience. Idealists and materialists take opposing positions on this question, the idealist claiming that physical objects are mind-dependent whereas the materialist claims that all that exists is physical.
But if we set out with the assumption that beliefs are rooted in evidence and can be altered by new or a reassessment of existing evidence, we will find little here to help us resolve this problem. What evidence supports or undermines the case that, for example, what we mean by a tree is an independently existing physical object rather than a collection of non-physical sense data in the mind? Neither the idealist nor the materialist is going to give ground in the way that we might be persuaded to do so by evidence of the existence or non-existence of a leopard, stegosaurus or black hole. This point highlights another feature of evidence as we ordinarily understand it, namely, that it tends to be cumulative. In the examples of leopard, stegosaurus and black hole one piece of evidence may be unconvincing. But when it is corroborated by more and more, then a new belief may be instigated or an old one swayed. Evidence has grown and reached a tipping point. By contrast, it is difficult to see how a switch from materialism to idealism or vice versa might be effected by virtue of the addition of extra items of evidence.
And, furthermore, the problem of our knowledge of the external world is, of course, not the only instance of a difficulty of a very fundamental kind that is not amenable to resolution by evidence. Consider also the long-standing difficulty of proving the existence of other minds or of providing a satisfactory theory of causation.
I am suggesting for consideration, then, the notion that the problem of the existence of God might have much in common with problems such as our knowledge of an external world, of other minds or of causation and as such is unlikely to be settled by the presentation or reassessment of evidence, even that in category c).
If not by evidence, then by what means are we to make progress towards a resolution of the problem? I take both the atheist and the theist positions to be coherent descriptions of reality in the sense that both give plausible explanations of phenomena we experience.
But what, essentially, is the difference between the systems of thought? In order to answer that question I shall first set out a very sketchy and minimalist description of a fundamental tenet of each, one that is sufficient only to highlight a central point of disagreement between them. (For this purpose I have merged the world view of the atheist with that of the physicalist, a conflation that admittedly may not be fair to either.)
a) atheist: first, that everything that exists is fundamentally physical and that, necessarily, there is no domain beyond the physical; second, that every event has a physical cause.
b) theist: that in addition to the physical as described above there exists a domain of the non-physical where God or ultimate value or a given purpose for human existence resides.
We are familiar with the dilemma of two coherent systems of thought coexisting, both offering an explanation of events and appealing for our consent. Think, for example, of the responses to the same set of economic data given by left and right wing political commentators. We are also familiar with historical examples of one coherent system being replaced by another, for example, Ptolemaic by Copernican astronomy, vitalism by a more mechanistic biology, steady state by big bang cosmology, Newtonian by Einstein's physics. In these cases we tend to regard the change as an advance from comparative ignorance to comparative knowledge, the system superseding its forerunner as epistemologically preferable. And there is ample justification for this assumption. In all the cases above the supplanting system is favoured because it works much more effectively: it fits the facts as known much more neatly; it admits of fewer anomalies, fewer instances of the inconsistent and unexplained.
The Times Atlas of the World is a much more helpful aid for travellers than the Mappa Mundi in Hereford Cathedral though both offer a coherent picture of the world. The lines and symbols of the former match many more of the places I am likely to encounter on a journey. In short, it is a better fit to what it is intended to map. I want to apply this analogy to the case in point and ask which of the two, atheism or theism, is the better map of reality? Now both systems will accept that events in the physical universe are the outcome of natural forces acting on material objects. The point of disagreement is not here but on the issue of whether this is a brute fact or part of a wider context.
The key question is this. Is a map of the physical universe identical with a map of the whole of reality? To put it slightly differently, if we have described every detail of the physical universe, is any domain of reality excluded from that description. A closely related question is debated in another philosophical area, the philosophy of mind and in particular the ancient and on-going debate as regards the ontological status of mind. For it is in this area that physicalism meets its most serious challenge. Is the mind to be counted as part of the physical universe or apart from it? And this debate is at its most divisive in connection with consciousness.
In the physicalist tradition (which is the line I am assuming the atheist will want to pursue) behaviourism, mind-brain identity theory and functionalism in different periods of dominance during the twentieth and into the twenty-first centuries have all sought to encompass consciousness within the physical. However, the debate is not at all one-sided with many philosophers taking the position that consciousness stubbornly refuses to be reduced to any physicalist explanation for several reasons as follows:
a) that the phenomenal ‘feel’ of conscious states cannot be captured in any description of brain states that accompany them
b) that, whereas physical objects are public, conscious states are private
c) that, whereas physical objects are extended, conscious states are non-dimensional
d) that, whereas physical objects have a location in space, conscious states are not spatially located
e) that, whereas the existence of physical objects is inferred, the existence of conscious states is known directly
f) that, whereas physical objects are known fallibly, conscious states are known infallibly.
It should be added that even among those who regard consciousness as a serious anomaly in a physicalist world view there is a significant difference of view. On the one hand, we find the belief that consciousness is problematic only because of the limits of present understanding and research and that within the potential compass of future understanding and research it will be accommodated. On the other hand, consciousness is held to be an insurmountable impasse, the ‘hard problem’ not temporarily but in the sense that it is in principle beyond resolution by the human intellect.
Now the first view is perfectly compatible with an atheist physicalism. The latter view, however, is not. If consciousness resists all attempts at a physicalist reduction, then it remains a feature of reality that the physicalist map has failed to represent, a piece of territory for which there is no corresponding representation.
It clearly does not follow from what I take to be a limitation of the atheist/physicalist position that the theist position has proved to be a perfect fit. Far from it. But at least it can be said that, unlike the atheist position, there is room within it for irreducible non-physicalism. There is at least some scope here to accommodate consciousness if it does indeed prove elusive to physicalist explanation. That very limited prospect is as much as can reasonably be claimed from this approach to the problem of the existence of God. And, of course, the details, implications and ramifications of this claim offer their own philosophical challenges
I began with a frequently cited justification for atheism, the lack-of-evidence of argument. I have tried to show that this view is rooted in a misunderstanding about evidence-based reasoning as regards this subject matter. I have certainly not attempted to make the contrary case, to present any revamp of an argument to prove the existence of God. That question, in my view, remains an open one and for greater elucidation we need to focus more attention on the very human problem of consciousness.
