"Suppose a surgeon has exposed an area of a patient’s brain, and because this contains no pain nerves the patient is conscious and able to report what is going on in her mind. Suppose she is visualizing a seaside bay, the waves sparkling in the sun, a harbour with moored fishing boats at the foot of a grassy cliff, and on top of that a ruined castle. It makes sense – whether true or false – to say that the electrical activity in the brain which the monitors are recording is causing this particular content of the patient’s consciousness (the ‘qualia’ in the philosophical jargon). It also makes sense – again whether true or false – to say that the visualizing could not occur without this particular brain activity. But does it make sense to say that the visualized scene literally is activity in the grey matter which the surgeon can see and touch? Surely this is not even a coherent possibility. There are no pictures or colours, no images of sea and harbour and fishing boats and castles on a hill, in the brain. There are synaptic connections between the millions of neurons, and electricity flowing through a region of these connections in a pattern which somehow either produces or is produced by this particular mental effort of imagination. But the extended and coloured picture which the patient is consciously visualizing is not itself any quantity of neurons or any flow of electricity."
In regards to epiphenomenalism – the belief that consciousness is non-physical, but that it is simply a temporary by-product of the physical activity in the brain and therefore unable to causally influence anything – Hick again finds this unsatisfactory for two reasons. First, he argues that, if consciousness is simply a by-product of physical events, there is no reason for consciousness to have developed evolutionarily. On the epiphenomenalist theory, it doesn't really "do anything"; the world would go on just as it would have had consciousness not developed. There is no survival value. Second, Hick argues that this theory rules out the possibility of true (i.e. "libertarian") free-will.
"There is also another anomaly of a different kind involved in any physicalism which involves either mind/brain identity or a purely epiphenomenal non-physical consciousness. For although there can be the illusion of freewill (‘compatibilist’ freewill) in a physically determined world, there can be no genuine (‘non-compatibilist’ or ‘libertarian’) freewill. But in that case, as Epicurus pointed out long ago, ‘He who says that all things happen of necessity cannot criticize another who says that not all things happen of necessity. For he has to admit that the assertion also happens of necessity’. In other words, if someone’s thought, ‘My every thought is physically determined’, is true, that thought itself is not the outcome of a process of free critical thinking but is an event determined by physical causes. Two people discussing together, one arguing for and the other against determinism, would be like two differently programmed computers producing different outcomes. It would require a non-determined programmer, exercising free rational judgment, to know which of them is programmed with the correct premises and the correct method of calculation. But according to determinism there are only the physically determined computers. To try to avoid this dilemma some have suggested that there is subatomic randomness within the causal processes in the brain, and that it is this randomness that makes free will possible. But this does not help. Randomness or chaos are just as incompatible with freewill as rigid causal determination. If every thought is either rigidly or randomly determined, we could never be in a state of rationally believing this to be the case. For rational believing presupposes a degree of intellectual freedom, the freedom to exercise judgment, and if all our thoughts are the result of either physical determination or random chance, we have no such freedom. In short, we cannot rationally believe ourselves to be totally determined entities."
For Hick, consciousness as a true determining agent, which we must assume in order to logically function in the world, is a mystery which should lead us to consider the existence of the ultimate non-physical reality – God. He concludes:
"...we are left with the mysterious but undeniable fact of consciousness as a non-physical reality, a reality which we have to assume is capable of free self-determining activity. This opens a window onto the possibility of the kind of non-physical reality to which the religions point as God, Brahman, the Dharmakaya and the Tao."
Windows in the Natural World and Human Life
Hick goes on to briefly address other aspects of the world which may be "signals of transcendence" depending on our interpretation. Hick lists:
(1) our experience of the beauty of the natural world,
"All of this (beauty in the natural world) can induce an awe, a responsiveness, a sense of wonder that is felt as a point of contact between our own spiritual nature and a greater spiritual reality within, around, and beyond us. "
(2) our experience of love among family and community,
"Yet other signals of transcendence come through our human neighbours. Love, not meaning here only sexual attraction, but going beyond this to a deep mutual commitment and caring for one another; or the sense of receiving a great gift and responsibility in the birth of a new life; or an encounter with the mysterious boundary when a loved one dies and yet continues to be loved; or co-operation and unity of spirit in a common cause, motivated by a common faith or ideology; or mutual support in the face of danger (in which even the madness of war can bring out qualities of heroism and altruism); or being part of a community in family, tribe, nation, the human race – all of these can evoke in a mind so disposed a sense of reality transcending our human concerns and yet impinging upon us through them, inscribing in our minds a great question mark that silently invites a response."
and (3) the testimony of "the saints" – those who have been transformed by their experience of the Divine to such a degree that they appear almost tangibly different than the rest of humanity.
"Even more powerful signals of transcendence come through goodness as embodied both in ordinary and in saintly people. In order to get away from the ecclesiastical associations of the word ‘saint’ I shall sometimes speak instead of mahatmas, great souls. A mahatma is a person who has undergone –usually very gradually –a transformation from natural self-centredness to a re-centring in the Transcendent, the Holy, the Divine, the Ultimate. The ego point of view has been very largely transcended and the individual has become ‘transparent’ to a greater reality that is now in varying degrees embodied, or incarnated, in him or her. The saints are crucial for our understanding of the nature of reality, and I am going to say more about them later. Part V could in fact have been incorporated at this point, and if any readers are inclined to read it next they should feel free to do so. As we have seen, humans have always tended to experience the natural in terms of the supra-natural, although of course that distinction would not have occurred to our early ancestors. They did not need any special pointers to the Transcendent because it was for them part of the normal fabric of life. But today most of us do need special pointers. And we can find them above all in the mahatmas, the great spirits of all traditions. It remains possible that the lives of those great spirits are based on delusion. But if we identify, and then discount, the pervasive naturalistic assumption of our culture, it is equally possible that the saints are not mistaken but are in fact more closely in touch with reality than the rest of us. In the end we are taking a cognitive and spiritual risk when we accept them as guides worthy to be followed, and equally so when we dismiss them as self-deceivers. The risk is, on the one hand, that of fooling ourselves by wishful thinking, and on the other hand, that of shutting out of our consciousness, at least for now, an immensely important fifth dimension of reality. "
So Hick ultimately argues that the apparent teleology of the cosmos, the nature of consciousness, anthropology (earlier in the book he referenced man having "an inbuilt tendency to experience the natural in terms of the super-natural"), our experience of natural beauty, the experience of love between individuals and in communities, and the testimony of the saints should lead us to consider the existence of God, a transcendent non-physical reality.
Other "arguments for the existence of God" which Hick doesn't mention include the cosmological / first mover argument, the argument from objective morality, the difficulty accounting for abiogenesis (the proposed natural explanations for "first life," which is also capable of reproduction), the apparent teleology of genetic code, etc.
I have long found the argument from the nature of DNA to be intriguing in this regard. Our DNA is encoded information. It is hard to imagine coded information that has a teleology of its own (i.e. it has functions it is "designed" to complete) originating from anything other than some kind of intelligent source. This is part of what caused Anthony Flew, controversially and toward the end of life, to become a theist. The following quotation is from his There is a God: How the World's Most Notorious Atheist Changed His Mind:
"A third philosophical dimension to the origin of life relates to the origin of the coding and information processing that is central to all life-forms. This is well described by the mathematician David Berlinski, who points out that there is a rich narrative drama surrounding our current understanding of the cell. The genetic message in DNA is duplicated in replication and then copied from DNA to RNA in transcription. Following this there is translation whereby the message from RNA is conveyed to the amino acids, and finally the amino acids are assembled into proteins. The cell’s two fundamentally different structures of information management and chemical activity are coordinated by the universal genetic code. The remarkable nature of this phenomenon becomes apparent when we highlight the word code. Berlinski writes: By itself, a code is familiar enough, an arbitrary mapping or a system of linkages between two discrete combinatorial objects. The Morse code, to take a familiar example, coordinates dashes and dots with letters of the alphabet. To note that codes are arbitrary is to note the distinction between a code and a purely physical connection between two objects. To note that codes embody mappings is to embed the concept of a code in mathematical language. To note that codes reflect a linkage of some sort is to return the concept of a code to its human uses. This in turn leads to the big question: ‘Can the origins of a system of coded chemistry be explained in a way that makes no appeal whatever to the kinds of facts that we otherwise invoke to explain codes and languages, systems of communication, the impress of ordinary words on the world of matter?’ Carl Woese, a leader in origin-of-life studies, draws attention to the philosophically puzzling nature of this phenomenon. Writing in the journal RNA, he says: ‘The coding, mechanistic, and evolutionary facets of the problem now became separate issues. The idea that gene expression, like gene replication, was underlain by some fundamental physical principle was gone.’ Not only is there no underlying physical principle, but the very existence of a code is a mystery. ‘The coding rules (the dictionary of codon assignments) are known. Yet they provide no clue as to why the code exists and why the mechanism of translation is what it is.’ He frankly admits that we do not know anything about the origin of such a system. ‘The origins of translation, that is before it became a true decoding mechanism, are for now lost in the dimness of the past, and I don’t wish to engage here in hand-waving speculations as to what polymerization processes might have preceded and given rise to it, or to speculate on the origins of tRNA, tRNA charging systems or the genetic code.’ Paul Davies highlights the same problem. He observes that most theories of biogenesis have concentrated on the chemistry of life, but ‘life is more than just complex chemical reactions. The cell is also an information storing, processing and replicating system. We need to explain the origin of this information, and the way in which the information processing machinery came to exist.’”