Darwin might never have written Origin of Species (Darwin, 1859) had it not been for the arrival of a paper that shook him to the core - a paper from Alfred Russel Wallace, wherein was set out, in essentials, the very theory of evolution which Darwin had already devised, but had not taken the time to refine and publish. In a flash, Darwin took pen in hand, and hammered out the immortal book that would supersede Wallace's work. All of this, of course, is but a tiny chapter in the history of science - with which many readers are doubtless familiar. Why mention it here? Well, Eccles calls himself a Darwinian, but actually he's a Wallacean - and there's a difference, a big difference between the two views. As Eccles explains, "Wallace felt that human intelligence could only be explained by the direct intervention of Cosmic intelligence" (Eccles, 1989, p. 235). This was a notion Darwin couldn't stomach. Wallace outraged Darwin by publishing a paper on primitive people (with whom he lived most of his life) in which he declared:
Natural Selection could only have endowed the savage with a brain a little superior to that of an ape, whereas he actually possesses one but a little inferior to that of the average members of our learned societies (Eccles, 1989, p. 235).
The notion that the powers possessed by homo sapiens sapiens (HSS) were created not by mindless processes, but by the Almighty, is one Eccles is quite at home with. Indeed, this book, despite it's empirical-sounding title, is in many ways a prolegomenon to Christian eschatology.
A casual reading may leave readers with the impression that Eccles is a Darwinian; a careful reading discloses the affinity to Wallace. We don't have the space here to retell the story even synoptically, but we can convey its gist.
Eccles' starts spinning his narrative in the preface, where he informs us that he has "been able to unfold the fascinating story of hominid evolution of the human brain" (Eccles, 1989, xi). But we soon see that there are two separate stories. The first spans the evolution of the mammalian brain from the primates to the emergence of homo sapiens (HS). The second story starts after the first ends, that is, after the brain of HS had arrived; it's the story of how we became - to use Eccles' phrase - human persons: incorporeal creatures able to control, and have experience through, human bodies.
The first story is in many ways told from the point of view of a detective recounting a solved case. Understanding the brain is made possible by inference from clues - such as changes in posture and locomotion. For example, Eccles infers from the famous footprints found at the Laetoli beds in Northern Tanzania that Australopithecus (A) was erect and bipedal. He also goes on to speak of human-like relationships among A; this Eccles infers from hand-holding, which is in turn inferred from the fact that the footprints in question are side-by-side. That some of the footprints are superimposed one upon another implies, by Eccles' lights, that A was capable of both a fairly high level of concentration and fine motor control. Eccles makes similar types of inferences from such evidence throughout the book.
Eccles' evolutionary story includes his discussion of the development of fine motor control from early primates to HS in connection with expansion of motor cortical representation for the thumb and fingers. He tells us that it wasn't until these features of the brain evolved that tool-making could occur. The idea is that the raw physical ability was present, but there was inadequate brain power.
This raises the obvious question: Why did these features of the brain evolve? In seeking an answer to this question one grasps the gist of Eccles' narrative, and one begins to see that Eccles and Darwin are worlds apart.
Eccles' answer to the question is that periods of stasis are punctuated by periods of rapid evolutionary change (speciation events), but with saltations and the creation of "hopeful monsters."
In a sense, the new function arises by serendipity, but Eccles seems to hold that there is indeed a reason for these changes, at least when it comes to the brain. So first we have bodies able to walk erect in bipedal fashion, and then comes the neural machinery able to control such bodies.
AS I SAID BEFORE -n similar theme in this forum- THIS IS NOT THE CASE, GENETICS HAVE PROVED THERE'S ALREADY THE MODEL OF AN ORGAN INSERTED EVEN IN THE MOST "PRIMITIVE" CREATURES WHO DIDN'T HAVE NOT EVEN THE ORGANS. So the argument "And first we have a hand physically able to build tools, and then comes the neural machinery enabling the use of such a hand. And first we have mechanisms allowing for the production of an array of sounds, and then comes the neural stuff that can put these mechanisms to work in communicating" has been demonstrated to be a mistake. In all these cases, the prior mechanism comes in order to get ready for the subsequent neurological advance. The ultimate trick of this type is the core of Eccles' second story: the advent of dualist interactionism: the arrival of certain neural machinery in primates makes it possible, many years later, for persons, existing in the non-physical world of the mental, to interact with and control bodies. Such an exotic and teleological scheme certainly is Wallace's (Clements, 1983). As Eccles proudly confesses:
I believe that biological evolution is not simply chance and necessity. That could never have produced us with our values. I can sense with [Sherrington] that evolution may be the instrument of a Purpose, lifting it beyond chance and necessity at least in the transcendence that brought forth human creatures gifted with self-consciousness (Eccles, 1989, p. 116).
3. Dualist Interactionism
What is dualist interactionism (DI)? : there are minds, incorporeal entities, and they interact somehow with physical brains.
The materialist critics argue that insuperable difficulties are encountered by the hypothesis that immaterial mental events such as thinking can act in any way on material structures such a neurons of the cerebral cortex... Such a presumed action is alleged to be incompatible with the conservation laws of physics, in particular of the first law of thermodynamics (Eccles, 1989, p. 187).
How does Eccles address this problem? By turning to quantum physics, specifically to the work of Margenau (1984):
Following Margenau, the hypothesis is that mind-brain interaction is analogous to a probability field of quantum mechanics, which has neither mass nor energy yet can cause effective action at microsites. More specifically it is proposed that the mental concentration involved in intentions or planned thinking can cause neural events by a process analogous to the probability fields of quantum mechanics (Eccles, 1989, p. 189).
Such a scheme isn't likely to make any philosophical headway, for the simple reason that that to which Eccles appeals here (as physicists and philosophers of science can confirm) is as controversial as interactionism itself.
Arguments for Dualist Interactionism?
Eccles' book is shockingly short on argumentation; we imagine that Eccles himself would confess that argumentation (at least of the rigorous variety) isn't intended to be the book's strong suit. However, a charitable reading (an extremely charitable reading) yields three arguments that can be reconstructed from the text. They are:
"The Brain Replacement Argument." The basic idea here is that most of your body is inessential. That is, we can cut off your foot, and replace it with a prosthesis, or even just leave you without it (if we take care of the bleeding). We can do this for your nose, your eyeballs, your hair... in fact, we can clearly do it for everything beneath your chin. And we don't even need to stop when we reach your brain. As Eccles points out (Eccles, 1989, p. 219), removal of the cerebellum gravely incapacitates movement, but the person is not otherwise affected. So we can keep going at least until we get to parts of your neo-cortex. Once at this point, we note that the physical stuff in question can be replaced with other physical stuff as long as the new stuff operates similarly - so how can a mind, a person, as a genuine thing that persists through time (an ens per se, to use the Latin), be a particular physical thing (an ens successivum)?
YET IF THERE'S NO PURPOSE, THE EXISTENCE ALLOW US TO ENJOY HAVING CLOR VISION, TONGUE TO TASTE THOUSANDS OF FLAVORS, EARS TO LISTEN IN STEREOPHONIC SOUND. Everything could well be done by evolution in a dull gray way, only feeding with something valuable but with bitter taste of a cactus.
"The Argument from the Failure of Evolution to Explain X." The argument here flows from a disjunction to the effect that every X is either explained in natural terms by evolution, or in terms that invoke a realm beyond the physical. Eccles intends that X be instantiated to phenomenal consciousness and he maintains that such consciousness cannot be explained in exclusively natural termsIf we have P-consciousness (as it certainly seems we do), and evolution can't explain it, then we seem to be sliding toward Wallace rather than Darwin: we seem to be sliding toward an explanation that goes beyond nature toward theism. That means believing in God's own system.
Daraio finds some arguments weak, because he is inclined to believe that there are naturalistic, evolutionary explanations for personhood and consciousness, though he certainly concedes that no such explanations are in hand.
Einstein, as much as anyone, employed this type of thinking; as is well-known, he sought to "become," for example, objects travelling at great speed (Einstein, 1952).