Process Philosophies - Mechanistic versus Transcendental
Philosophies are either process or substantive (otherwise known as substantialist, essentialist or reifying). The former type of philosophy regards process and impermanence as being the fundamental features of existence. The latter regards things, substances and/or their defining 'essences' as being primary.
Both types of philosophy can be further subdivided into mechanistic or transcendental. Mechanistic philosophies state that only physical things or physical processes are required to completely explain the universe. Transcendental philosophies claim that physical matter or processes are inadequate to explain the universe, in particular the activities of the human mind and its products. All spiritual paths are transcendental in that they refuse to reduce qualitative aspects of human nature such as love, compassion, appreciation of beauty and freewill to 'nothing but' physical substances or interactions.
We thus have the following combinations:
(e.g. nineteenth century atomic materialism)
Mechanistic substantive materialism believed that atoms were solid chunks of matter embodying the unchanging qualities of the elements. During the 20th century this has been superseded by physicalism, which views matter as being a manifestation of quantum interactions and processes. A fundamental particle isn't actually a 'thing', it's a mathematical process known as a superposition.
The worldview of quantum physics differs radically from that of classical physics. Classical physics regards the universe as being composed of clearly-defined building blocks ('things') which are specified by their own internal properties. Quantum physics sees the universe as an ever-changing set of relationships between entities which can be defined only in terms of those relationships.
The traditional Copenhagen interpretation of Quantum mechanics regards subatomic entities as having a dual nature - sometimes they behave as particles ('things') and sometimes as waves ('processes' ). However recent work by Shahriar S. Afshar  suggests that there is 'no such thing as a photon' , and the fundamental nature of all 'particles' is actually wavelike processes.
So when you get down to the actual nitty-griitty of what all 'things' are made of, you find there's no-thing there. It's processes and impermanence all the way up and processes and impermanence all the way down.
Transcendental substantive philosophers believed that all things including the species of plants and animals derived their 'defining essence' from 'special creation' according to 'universals' in the mind of God. Thus the herring gull is a different species from the lesser black-backed gull because they are derived from two different patterns in God's mind. The doctrine of special creation and the associated idea of essentialism were demolished by Darwin 150 years ago.
So the substantive philosophies can be discarded as being obsolete.
Thus we are left with the two types of process
philosophies - mechanistic and transcendental.
Is there a spiritual dimension to life or is everything reducible to physical interactions?
Mechanistic process philosophy is usually called 'physicalism' as distinct from the non-process materialism of earlier centuries. Physicalism implies that it is possible to construct a universal machine which can do anything that the human mind can do. Consequently, if the human mind can be shown to do things which are impossible for a machiine, then physicalism is disproved.
Physicalism states that all processes can be explained in terms of causal relationships bringing about changes in structural relationships. All the phenomena in the universe can thus be simulated on a general purpose computer where the causal relationships are implemented as procedures (eg Fortran, C, Visual Basic) and the structural relationships are implemented as datastructures such as a relational database. With procedures and data you can simulate any process. The operating system allows as many processes as are necessary to be run in parallel and to communicate with one another. There is therefore no reason why a computer should not be able to perform all the mental processes of a human being. The proof of this would be for the computer to pass the Turing test. That is to be able to converse with humans (say by e-mail) with the humans not being able to tell that they were communicating with a machine.
It is now half a century since Turing formulated his test and no machine has come near to passing it. This has led many philosophers as well as computer engineers to wonder why. What sort of things does the human mind do that a physical system can't?
Does this suggest that mental processes are
part of a 'transcendental aspect of reality', for want of a better term ?
Types of transcendental process philosophy
Buddhism is the only major form of transcendental process philosophy existing at the present day. There is some evidence that Druidry was a transcendental process philosophy, but I have never seen any Druid critiques of physicalism.
Whitehead's process theology was similar to Buddhism in many respects. It was an attempt to give Christianity a rational underpinning using Buddhist metaphysics. As Whitehead said "Christianity ... has always been a religion seeking a metaphysic, in contrast to Buddhism which is a metaphysic generating a religion."
Whitehead's views never became mainstream. Nowadays, with the demise of Christian philosophy due to the increasingly anti-intellectual climate and growing influence of fundamentalists, creationists and inerrantists within the churches, they are even less likely to be acceptable to the majority of Christians.
So if there's going to be an effective
critique of physicalism, it can only come from Buddhists.
Buddhism versus physicalism
Before we take a look at the Buddhist critique of physicalism, it should be understood that Buddhists are not opposed to physicalism in the way that Christians are opposed to Darwinism. Buddhists don't reject physicalism or believe that it's wrong. They just think that it's incomplete because it doesn't acknowledge mental phenomena as being transcendental aspects of existence that can't be explained in purely physical terms.
Most Buddhists are quite happy with the theory of evolution, since all phenomena are impermanent, including species. In fact, the growth of Buddhism in the West (especially in academic circles) has probably been helped by the destruction of essentialism which began with Darwin in biology, and as Daniel Dennett noted , has since spread to other phenomena and other disciplines.
Mind versus Machine
Similar arguments that the mind can understand what a machine cannot have been developed by the eminent physicist Sir Roger Penrose, whose work has done much to lead to the 'rediscovery of the mind' which took place among philosophers in the 1990s.
The loss of meaning
If Tank3Level = Hi and Tank4Level = Lo then Call AdjustTankLevel
But meaningful for whom. For other programmers? For myself in six months time? For the code inspectors? Certainly not for the computer, because the computer has to strip out all meaning from its instructions before it can execute them. (A process known in the trade as 'compilation') The computer turns all its variables and subroutine names into arbitrarily numbered addresses. So the instruction
If Three = 1 and Four = 0 then Call AuntGertrude
would have worked just as well, because all that appears to the computer program is a linear series of boxes and an instruction such as
If there is 1 in Box3 and 0 in Box4 go and carry out the procedure which starts at Box 600
This approach has been further developed by John Searle in the famous Chinese Room Argument against machine intelligence, which demonstrates that a machine cannot understand what it is doing or why.
So, the word 'mind' could be partially defined as 'that which gives meaning'. Indeed the words 'mind' and 'meaning' derive from the same Indo-European root . They are also probably related the Sanskrit 'manas'. (Oddly enough, although English and Sanskrit have words for 'mind', many other Indo-European languages do not. Translation of 'mind' into French or German and retranslation back to English will give something like 'soul', 'spirit' or 'ghost').
The arguments set out above demonstrate that procedure and structure as implemented on any sort of physical machine are inadequate to describe the capabilities of human mental processes. (See computationalism). This limitation will not be solved by hardware improvements.
No matter how many terabytes, gigaflops, neural nets or iterations of Moore's law we throw at the problem of producing artifical intelligence, the difficulties will remain insurmountable as long as the hardware is only capable of dealing with truth values which can be treated as binary or numeric, and as long as compilers strip out all meaning from the source code in the process of producing machine code.
But what other architecture is there?
Notes and references
 Dennett, Daniel C in 'Darwin's Dangerous Idea ' p 36 -39; publ Penguin, London 1996, ISBN 0-14-016734-X
 Etymology of mean (1) in Oxford Concise English Dictionary, Ninth Edition p 844, publ Clarendon Press Oxford 1995, ISBN 0-19-861319-9
 Quantum processes