Free Will, Agency, Self, and Life, part 6; Brain as Meat Machine

Free Will Part 6 Brain as Meat Machine

As part of the Free Will and Agency discussion we need to address the issue of whether the brain is a machine. It has been posited that the brain is nothing more than a “meat machine”, and this proposition has been carried forth by the warriors in the battle to create Artificial Intelligence. The Turing-Church thesis goes back over half a century, to at least 1937, and was stated in 1939 as follows,

" It was stated ... that 'a function is effectively calculable if its values can be found by some purely mechanical process.' We may take this literally, understanding that by a purely mechanical process one which could be carried out by a machine. The development ... leads to ... an identification of computability † with effective calculability"
(Turing 1939)

"†We shall use the expression "computable function" to mean a function calculable by a machine, and we let "effectively calculable" refer to the intuitive idea without particular identification with any one of these definitions."
(Turing 1965)

http://psychology.wikia.com/wiki/Church-Turing_thesis

The Turing Church thesis and its ancestors became foundational in computing, and by extension have been carried over to theories of mind. Or have they?

Turing-Church has been misunderstood, and consequently misapplied:

From plato.stanford:

A myth seems to have arisen concerning Turing's paper of 1936, namely that he there gave a treatment of the limits of mechanism and established a fundamental result to the effect that the universal Turing machine can simulate the behaviour of any machine. The myth has passed into the philosophy of mind, generally to pernicious effect. For example, the Oxford Companion to the Mind states: "Turing showed that his very simple machine ... can specify the steps required for the solution of any problem that can be solved by instructions, explicitly stated rules, or procedures" (Gregory 1987: 784). Dennett maintains that "Turing had proven - and this is probably his greatest contribution - that his Universal Turing machine can compute any function that any computer, with any architecture, can compute" (1991: 215); also that every "task for which there is a clear recipe composed of simple steps can be performed by a very simple computer, a universal Turing machine, the universal recipe-follower" (1978:. xviii). Paul and Patricia Churchland assert that Turing's "results entail something remarkable, namely that a standard digital computer, given only the right program, a large enough memory and sufficient time, can compute any rule-governed input-output function. That is, it can display any systematic pattern of responses to the environment whatsoever" (1990: 26). These various quotations are typical of current writing on the foundations of the computational theory of mind. It seems on the surface unlikely that these authors mean to restrict the general notions of ‘explicitly stated rule’, ‘instruction’, ‘clear recipe composed of simple steps', ‘computer with any architecture’,‘rule-governed function’ and ‘systematic pattern’ so as to apply only to things that can be obeyed, simulated, calculated, or produced by a machine that implements ‘effective’ methods in Turing's original sense. But unless these notions are restricted in this way from the start, we should reject such claims.

Turing did not show that his machines can solve any problem that can be solved "by instructions, explicitly stated rules, or procedures", nor did he prove that the universal Turing machine "can compute any function that any computer, with any architecture, can compute". He proved that his universal machine can compute any function that any Turing machine can compute; and he put forward, and advanced philosophical arguments in support of, the thesis here called Turing's thesis. But a thesis concerning the extent of effective methods -- which is to say, concerning the extent of procedures of a certain sort that a human being unaided by machinery is capable of carrying out -- carries no implication concerning the extent of the procedures that machines are capable of carrying out, even machines acting in accordance with ‘explicitly stated rules’. For among a machine's repertoire of atomic operations there may be those that no human being unaided by machinery can perform.

The further proposition, very different from Turing's own thesis, that a Turing machine can compute whatever can be computed by any machine working on finite data in accordance with a finite program of instructions, is sometimes also referred to as (a version of) the Church-Turing thesis or Church's thesis. For example, Smolensky says:

connectionist models ... may possibly even challenge the strong construal of Church's Thesis as the claim that the class of well-defined computations is exhausted by those of Turing machines. (Smolensky 1988: 3.)

This loosening of established terminology is unfortunate, for neither Church nor Turing endorsed, or even formulated, this further proposition. There are numerous examples of this extended usage in the literature. The following are typical.

That there exists a most general formulation of machine and that it leads to a unique set of input-output functions has come to be called Church's thesis. (Newell 1980: 150.)

[T]he work of Church and Turing fundamentally connects computers and Turing machines. The limits of Turing machines, according to the Church-Turing thesis, also describe the theoretical limits of all computers. (McArthur 1991: 401.)

[I]t is difficult to see how any language that could actually be run on a physical computer could do more than Fortran can do. The idea that there is no such language is called Church's thesis. (Geroch and Hartle 1986: 539.)

Also (more distant still from anything that Church or Turing actually wrote):
I can now state the physical version of the Church-Turing principle: "Every finitely realizable physical system can be perfectly simulated by a universal model computing machine operating by finite means." This formulation is both better defined and more physical than Turing's own way of expressing it. (Deutsch 1985: 99.)


This formulation may be ‘more physical’ than Turing's own, but it is scarcely ‘better defined’. The notion of an effective method played an important role in early debates about the foundations of mathematics, and it was sufficiently clear to allow Turing, Church, and others to recognize that different formal accounts gave alternative modellings of the notion. Their notion was certainly not that of a ‘finitely realizable physical system’.
J. B. Copeland, plato.stanford.edu

One of the misapprehensions of Turing-Church is that the human brain is a Turing machine, with all of its functions describable by calculable algorithms which are therefore transferrable to other computing devices. This is the thrust of the notion that the brain/mind is just a “meat machine”, a term used by AI researcher Marvin Minsky, MIT.

If the brain/mind truly is merely a meat machine, then it is wholly unremarkable. Moreover, it cannot possess any features which an ordinary machine does not possess, nor produce any products which an ordinary machine could not produce. Ordinary machines are not known to create new or innovative responses which are not predetermined by their makeup and environment: they respond with total abeyance to deterministic conditions. By this reduction, then, the human brain/mind can exhibit no creative or innovative responses and is restricted to deterministic behaviors as controlled by internal algorithms working on current environmental inputs.

This determinism absolutely precludes any free will, free choice or agency (intentionality), as well as creativity and transcendence into abstractions. That would have precluded Turing and Church from producing a generalized theory of computation in the first place, of course, as well as precluding the use of their thesis in hypothetical philosophies (however flawed or misappropriated).

While the conclusion that brain/mind is deterministic might be necessary for thinking that machines can be endowed with actual artificial intelligence, it contradicts human experience and is therefore non-empirical, to say the least. But it has another use too.

The reduction of human mind/brain to machine status is necessary in order to sustain the Philosophical Materialist tenet that because physical existence is all that there is, then the rules of physics are universally applicable, including to human brain/mind activities. Since determinism is an underlying axiom of physics, then the human brain/mind has to be deterministic under PM:

P1: IF [Philosophical Materialism], THEN [human brain/mind=deterministic].

P2: [Philosophical Materialism].

C: THEREFORE: [human brain/mind=deterministic].

Here we see that the conclusion is determined by the philosophy, not by any empirical data or evidence. Under rational processes, the empirical data would determine the validity of the theory, not the other way around. By reversing this process, the holder of Philosophical Materialism has created a dogma, one with a contradiction to empirical understanding. This reveals yet another defect in the philosophy of Materialism: if the human mind is as it seems, which is a non-deterministic agent with the ability to cause material changes through mental initiation, then at least something in the universe is not deterministic, is an uncaused causer, and does not fit the concept of “materialness”. The existence of such a thing is enough to refute Philosophical Materialism.

So back to the above argument, under the auspices of logical rigor it can be seen that P1 is false, P2 is false, and the conclusion is false. But we can redesign a syllogism with proper statements and premises to reflect what the expectations of the real world would be. Restating for proper structure and premises:

P1: IF [human brain/mind=deterministic], THEN [this proposition and all propositions have no truth value (meaning)].

P2: IF [all propositions have no truth value or meaning], THEN [Philosophical Materialism is meaningless].

C: THEREFORE [Philosophical Materialism is meaningless].

Note that P1, even though stating the concept properly, is internally non-coherent because the conclusion negates the premise; P1 cannot be true. Yet it is a natural outgrowth of the deterministic, meat machine model of human brain/mind. In the end, Philosophical Materialism has created still another internal contradiction for itself.

Obviously no Materialist believes this conclusion. So the options available for salvaging Philosophical Materialism are (a) to ignore the logical disproof, (b) to redefine determinism, (c) to redefine agency, (d) to redefine both determinism and agency so that they are somehow thought to be compatible (aka “Compatibilism).

Compatibilism will be the next subject.