I would like to begin by congratulating Kantian Naturalist on his recent post, Solving Wallace’s Problem and Resolving Darwin’s Doubt, which squarely faces the epistemological issues raised by Darwin and Wallace, regarding the reliability of human knowledge. In this post, I’d like to explain why I don’t think Kantian Naturalist’s statement of the problem quite gets it right, and why I believe the solution he puts forward is a flawed one.

Wallace’s problem

Let’s begin with Wallace’s difficulty, which he discussed towards the end of his review of Charles Lyell’s Principles of Geology and Elements of Geology, which was published in the April 1869 issue of the Quarterly Review. On page 392 of the review, Wallace expresses his astonishment at the fact that people in all ethnic groups have brains with virtually identical capacities, regardless of their level of intellectual development: “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 very little inferior to that of the average members of our learned societies.” Wallace rhetorically asked: “How, then, was an organ developed so far beyond the needs of its possessor?” Wallace applied the same argument to the organs of speech, remarking that “among the lowest savages with the least copious vocabularies, the capacity of uttering a variety of distinct articulate sounds, and of applying to them an almost infinite amount of modulation and inflection, is not in any way inferior to that of the higher races.” Once again, the level of development struck Wallace as biologically superfluous: “An instrument has been developed in advance of the needs of its possessor.” Wallace proposed that just as man has “directed the action of the laws of variation, multiplication, and survival, for his own purposes” when artificially breeding crops and domestic animals, so too, a Higher Intelligence has “guided the same laws for nobler ends… in the development of the human race.”

It is worth noting that the foregoing argument of Wallace’s is a purely biological argument: natural selection lacks foresight, and is therefore unable to account for the development of an organ which will be biologically advantageous in the future, but which (he believed) confers no advantage at present, in many human societies. This argument is quite distinct from Wallace’s philosophical argument, made in the same review: “Neither natural selection nor the more general theory of evolution can give any account whatever of the origin of sensational or conscious life.” The laws of Nature could generate complex bodies through the process of natural selection, but these laws “cannot even be conceived as endowing the newly-arranged atoms with consciousness.” (I am reminded here of Thomas Nagel’s claim, in his now-famous paper, What is it like to be a bat?, that “Consciousness is what makes the mind-body problem really intractable.”) Nor can any law of evolution account for “the moral and higher intellectual nature of man,” in Wallace’s view.

If we examine Wallace’s biological argument, we find that it was answered fairly comprehensively by Thomas Henry Huxley in his 1871 essay, Mr. Darwin’s Critics. First, Huxley pointed out that the so-called “savage” races faced cognitive challenges far more formidable than those faced by people living in “advanced” societies:

…[C]onsider that even an Australian [Aborigine] can make excellent baskets and nets, and neatly fitted and beautifully balanced spears, that he learns to use these so as to be able to transfix a quartern loaf at sixty yards; and that very often, as in the case of the American Indians, the language of a savage exhibits complexities which a well-trained European finds it difficult to master: consider that every time a savage tracks [176] his game he employs a minuteness of observation, and an accuracy of inductive and deductive reasoning which, applied to other matters, would assure some reputation to a man of science, and I think we need ask no further why he possesses such a fair supply of brains. In complexity and difficulty, I should say that the intellectual labour of a “good hunter or warrior” considerably exceeds that of an ordinary Englishman.

Additionally, Huxley contended that there was a strong selective effect favoring individuals possessing “intellectual or aesthetic excellence,” even in the most technologically backward societies:

The savage who can amuse his fellows by telling a good story over the nightly fire, is held by them in esteem and rewarded, in one way or another, for so doing–in other words, it is an advantage to him to possess this power. He who can carve a paddle, or the figure-head of a canoe better, similarly profits beyond his duller neighbour. He who counts a little better than others, gets most yams when barter is going on, and forms the shrewdest estimate of the numbers of an opposing tribe… If we admit, as Mr. Wallace does, that the lowest savages are not raised “many grades above the elephant and the ape;” and if we further admit, as I contend must be admitted, that the conditions of social life tend, powerfully, to [179] give an advantage to those individuals who vary in the direction of intellectual or aesthetic excellence, what is there to interfere with the belief that these higher faculties, like the rest, owe their development to natural selection?

In my humble opinion, Huxley got the better of Wallace in this exchange, leaving Wallace’s argument from the alleged surplus capacity of the human brain in tatters. I am therefore utterly mystified at Kantian Naturalist’s assertion, in his post, that the answer to “Wallace’s problem,” as he calls it, required not only a philosophical revolution (viz. the notion that language is logically prior to thought, and not merely the vehicle by which thoughts are communicated), but additionally, scientific developments in the fields of “niche construction theory, embodied-embedded cognitive science, comparative primatology, and paleoanthropology (none of which were available to Wallace or Darwin).”

As we saw above, Wallace’s philosophical argument against the mind being a product of natural selection rested on the claim that there was a sharp discontinuity between conscious and unconscious creatures, and between humans, with their moral and intellectual capacities, and other animals, which lacked these capacities. Once again, we find that replies were forthcoming from the scientific community, even back in Wallace’s day. In his work, The Descent of Man, and Selection in Relation to Sex (London: John Murray, 1st edition, 1871), Charles Darwin argued that the difference between man and the apes was one of degree rather than kind, and that it was dwarfed by the far greater differences in mental capacities between apes and the “lower” animals:

If no organic being excepting man had possessed any mental power, or if his powers had been of a wholly different nature from those of the lower animals, then we should never have been able to convince ourselves that our high faculties had been gradually developed. But it can be clearly shewn that there is no fundamental difference of this kind. We must also admit that there is a much wider interval in mental power between one of the lowest fishes, as a lamprey or lancelet, and one of the higher apes, than between an ape and man; yet this immense interval is filled up by numberless gradations. (Chapter II, p. 35)

Nevertheless the difference in mind between man and the higher animals, great as it is, is certainly one of degree and not of kind. (Chapter III, p. 105)

…[T]he mental faculties of man and the lower animals do not differ in kind, although immensely in degree. A difference in degree, however great, does not justify us in placing man in a distinct kingdom, as will perhaps be best illustrated by comparing the mental powers of two insects, namely, a coccus or scale-insect and an ant, which undoubtedly belong to the same class. The difference is here greater than, though of a somewhat different kind from, that between man and the highest mammal. (Chapter VI, p. 186)

On the whole, the difference in mental power between an ant and a coccus is immense; yet no one has ever dreamed of placing them in distinct classes, much less in distinct kingdoms. No doubt this interval is bridged over by the intermediate mental powers of many other insects; and this is not the case with man and the higher apes. (Chapter VI, p. 187)

I therefore cannot concur with Kantian Naturalist’s assessment that “[w]hereas Darwin thought there was continuity between humans and non-human animals, his evidence is primarily about emotional displays, rather than the genuinely cognitive discontinuity.” Indeed, chapters II and III of Darwin’s Descent of Man can be described as a systematic attempt to prove that the moral and intellectual difference in capacity between man and the other animals is merely one of degree, rather than kind. As a dualist, I am not at all persuaded that the attempt works. But if I were asked who got the better of the exchange between Darwin and Wallace on this point, I would have to say: Darwin.

Notwithstanding this admission on my part, I would like to point out that oft-repeated claims of a cognitive continuum between man and the other animals rest on faulty science. Unfortunately, in Darwin and Wallace’s day, the scientific experiments lending support to the hypothesis of human uniqueness had not yet been performed. Three years ago, I presented the evidence for human uniqueness in a series of essays on Uncommon Descent, which readers are welcome to peruse at their own leisure:

The Myth of the Continuum of Creatures: A Reply to John Jeremiah Sullivan (Part One)
The Myth of the Continuum of Creatures: A Reply to John Jeremiah Sullivan (Part Two)
The Myth of the Continuum of Creatures: A Reply to John Jeremiah Sullivan (Part 3(a))
The Myth of the Continuum of Creatures: A Reply to John Jeremiah Sullivan (Part 3(b))

As Kantian Naturalist correctly points out, Wallace wasn’t the only one with doubts. It turns out that Darwin had doubts of his own about the reliability of human cognition, and it is to these that I now turn.

Darwin’s Doubt

Here’s how Kantian Naturalist summarizes Darwin’s “horrid doubt”:

A closely related problem, however, was squarely faced by Darwin: the question, nicely phrased in his famous letter to Asa Gray, as to whether it is plausible to think that natural selection can have equipped a creature with a capacity for arriving at any objective truths about the world. (It is not often noted that in that letter, Darwin says that he believes in an intelligent creator — what is in doubt is whether natural selection gives him reasons to trust in his cognitive abilities.)

These two questions, Wallace’s Problem and Darwin’s Doubt, are two sides of the same coin: if natural selection (along with other biological processes) cannot account for the uniquely human ability to grasp objective truths about reality, then we must either reject naturalism (as Wallace did) or question our ability to grasp objective truths about reality (as Darwin did).

Call this the Cognitive Dilemma for Naturalism. Can it be solved? If so, how?

It appears that Kantian Naturalist is referring to Darwin’s letter of May 22, 1860 to the American botanist Asa Gray (1810-1888), in which Darwin affirms that, although he does not believe in the necessity of a design in nature, he finds it difficult to believe that everything is the result of “brute force.” After tentatively suggesting that everything results from “designed laws, with the details, whether good or bad, left to the working out of what we may call chance,” Darwin concludes by saying that the whole subject of God’s existence and nature is “too profound for the human intellect.”

However, the phrase “Darwin’s horrid doubt” comes from Darwin’s 1881 letter to William Graham, in which he wrote:

…I have had no practice in abstract reasoning, and I may be all astray. Nevertheless you have expressed my inward conviction, though far more vividly and clearly than I could have done, that the Universe is not the result of chance. But then with me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?

As the Australian philosopher John S. Wilkins points out in a 2010 essay titled, You and me, baby, ain’t nothing but mammals on his blog, Evolving Thoughts, Darwin’s doubt had nothing to do with how we are able to grasp objective truths about the world:

First, let’s dispose of one point: Darwin’s Monkey Mind Puzzle was not aimed at debunking our knowledge of the natural world. He did not admit a fatal flaw in his own metaphysics or epistemology…

Darwin’s “horrid doubt” is whether we can know anything about God, not the world…

The same remarks apply to Darwin’s 1860 letter to Asa Gray: here, once again, Darwin suggests that the human mind is liable to err when it engages in abstruse theological reasoning. Nowhere, however, does he express doubts about the reliability of our reasoning processes, when applied to the natural world.

Our knowledge of the external world: problem solved?

In his 2010 essay, You and me, baby, ain’t nothing but mammals, philosopher John S. Wilkins addresses the question of whether Darwin’s theory supplies sufficient warrant for our belief that our scientific theories (including the theory of evolution) truly describe the world. He concludes that it does, because our theories are carefully constructed on the basis of our observations of not only near objects, but also increasingly distant ones, enabling us to gradually extend the scope of our generalizations:

So to the main point: if evolutionary theory is true, then are we blocked from thinking that it is true? Clearly not. If it is true then there is no contradiction with our beliefs being formed on the basis of evolutionary processes also being true…

When true beliefs are causally relevant to fitness, then we might expect organisms, including those endowed with monkey minds, to be able to track truth. Species that have nervous systems respond to environmental cues that are highly relevant to their fitness: von Uexküll called this the Umwelt. The world of primate common sense is our Umwelt.

Scientific theories bootstrap on this Umwelt; we begin by testing distal claims by ordinary observation, and then extend our theoretical reach by increasingly theoretical, but tested and grounded in our Umwelt, observations, as Ian Hacking argued in Representing and Intervening. Science tracks truth because it is able to rely on some degree of truthlikeness for the observational reports that we can generate in our protoscience.

However, I don’t think this answer will do. The problem with this view is that it assumes that as we refine our observations, we will eventually be left with a single theory which leaps out at us, as it were. In reality, this never happens. Scientists have no way of showing that a given theory is the only way of explaining our observational data. There are always choices to be made between rival theories that can account for the same data, and quite often they are made on aesthetic grounds: we tend to prefer simple, elegant theories. But as Oscar Wilde wittily observed, “The truth is rarely pure and never simple.” Our preference for simplicity, elegance and ease of comprehension is a human projection on Nature – one which would make no sense unless we assumed that Nature was designed to be comprehensible, as many theists do. If an atheist wishes to refrain from making this assumption, then it seems to me that an anti-realist view of scientific truth is the only logical alternative. On this view, we should not say that unobservable or theoretical entities actually exist, but merely that they are useful constructs for helping us to make predictions about future observations. But if that’s correct, then is macroevolution real? Hmmm.

To sum up: it seems to me that Darwin’s theory of evolution gives us good reason to believe in the predictions made by our scientific theories, but little reason to believe that those theories are objectively true, insofar as they postulate theoretical entities which go beyond the limit of our observations. All we can say is that science works.

So, what about Kantian Naturalist’s solution to the Cognitive Dilemma for Naturalism?

Kantian Naturalist thinks he can solve what he refers to as the Cognitive Dilemma for Naturalism, by a two-step process, which he helpfully explains in a comment on his post:

There are two distinct moves here.

The first is a philosophical move, in which we see language as underpinning and making possible, both in evolution and in development, abstract thought, symbolic communication, self-consciousness, and objectivity. (That’s what I’m calling ’embodied discursive pragmatism’.)

The second is a scientific move, in which we understand how language is a result of evolution (more precisely: the co-evolution of language and human cognition).

Kantian Naturalist’s philosophical claim that language is logically prior to abstract thought has attracted a lot of criticism, most of which I think this is unjustifiably harsh. Having studied Wittgenstein’s thinking in some depth at university, I can appreciate Kantian Naturalist’s insistence that language and thought are inter-twined. While I would not say that the former precedes the latter, I would wholeheartedly agree with Kantian Naturalist’s rejection of the naive view that language is merely a vehicle or tool for expressing our thoughts.

Instead, my criticisms will be directed at Kantian Naturalist’s scientific claim that the origin of language can be understood in evolutionary terms: in particular, that niche construction theory may have driven the evolution of language and shared intentionality.

…[T]he construction of a uniquely hominid niche involved obligate cooperative extractive foraging. While extractive foraging is common in primates, and many great apes use tools to extract foods from their environments, humans are cooperative in extractive foraging (and must be so). Adequate provisioning requires that everyone in the group who is able to contribute will in fact contribute to the provisioning of everyone else, through division of labor that involves hunting and scavenging; setting traps for small animals; gathering nuts, seeds, berries and herbs for foods and medicines; cleaning and cooking food, making clothing, weapons; transmitting to future generations the knowledge of how to do all these things through active teaching.

Obligate cooperative foraging involves two important cognitive transformations: displaced reference and joint intentionality. Displaced reference, which put hominids on the road to language, is the capacity to communicate about objects and events that are not perceptually present to (at least) the hearer. Joint intentionality is the ability for two creatures to take an object as their shared object of attention, to know of the other creature that it is also attending to that object and to want them to do so, so that the two creatures can coordinate their actions in order to succeed at a task that neither of them could accomplish alone (or which would take much more time or energy to do so).

Frankly, I don’t buy this story, for several reasons.

First, arguing that language would have been beneficial to human survival, if it arose, fails to explain how it arose. “Why” is not the same thing as “how.” I was shocked to see so many commenters fall into this teleological mode of explanation. Here’s a case in point:

Social groups need to communicate. In a forest niche, vocal communication has advantages over visual communication and signalling.

I could just as well argue that telepathy has great advantages over vocal communication, but that wouldn’t explain how it evolved. In fact, it wouldn’t even tell us whether telepathy could have evolved. We need a mechanism.

Second, there are plenty of animals which engage in niche construction (e.g. beavers), co-operative hunting (e.g. lions) and extractive foraging (e.g. chimps), without the benefit of language. I’m not at all convinced that a lifestyle combining these various behaviors (such as that of our hominin ancestors) would have necessitated the use of language, either. I don’t see why we need language for “gathering nuts, seeds, berries and herbs for foods and medicines,” or for “cleaning and cooking food.” As for cultural transmission of skills to future generations, this is something we observe in non-human animals as well. Making clothing is unlikely to be what necessitated the use of language, as clothing is a relatively recent invention, probably coinciding with the appearance of anatomically modern humans in Africa, around 200,000 years ago. Language, on the other hand, probably goes back at least to the common ancestor of Homo sapiens and Neanderthal man, as Dan Dediu and Steven Levinson have argued at length in their article, On the antiquity of language: the reinterpretation of Neandertal linguistic capacities and its consequences (in Frontiers in Psychology, 4:397. doi: 10.3389/fpsyg.2013.00397):

The Neandertals had a complex stone tool technology (the Mousterian) that required considerable skill and training, with many variants and elaborations (see Klein, 2009: 485ff). They sometimes mined the raw materials at up to 2 meters depth (Verri et al., 2004). Their stone tools show wear indicating usage on wood, suggesting the existence of a wooden material culture with poor preservation, such as the carefully shaped javelins made ~400 kya [about 400,000 years ago – VJT] from Germany (Thieme, 1997). Tools were hafted with pitch extracted by fire (Roebroeks and Villa, 2011). Complex tool making of the Mousterian kind involves hierarchical planning with recursive sub-stages (Stout, 2011) which activates Broca’s area just as in analogous linguistic tasks (Stout and Chaminade, 2012). The chain of fifty or so actions and the motor control required to master it are not dissimilar to the complex cognition and motor control involved in language (and similarly takes months of learning to replicate by modern students).

Additionally, a 2011 essay by Dietrich Stout and Thierry Chaminade, titled, Stone tools, language and the brain in human evolution (Philosophical Transactions of the Royal Society B, 12 January 2012, vol. 367, no. 1585, pp. 75-87) lends support to the view that the Late Acheulean tools made by Heidelberg man required a high level of cognitive sophistication to produce, in addition to long hours of training for novices. This training would have included the use of intentional communication, which the authors characterize as “purposeful communication through demonstrations intended to impart generalizable (i.e. semantic) knowledge about technological means and goals, without necessarily involving pantomime.”

Third, I should point out that the evidence for the extractive foraging hypothesis is not terribly strong. Another popular theory is the social brain hypothesis, but that seems to have problems, too, as does the recent theory that cooking helped big brains evolve.

Finally, I’d like to draw readers’ attention to a quote from writer and columnist A. N. Wilson, a convert from atheism, who argued that materialist accounts of the origin of language are inherently inadequate, in a hard-hitting article titled, Why I believe again (New Statesman, 2 April 2009):

Do materialists really think that language just “evolved”, like finches’ beaks, or have they simply never thought about the matter rationally? Where’s the evidence? How could it come about that human beings all agreed that particular grunts carried particular connotations? How could it have come about that groups of anthropoid apes developed the amazing morphological complexity of a single sentence, let alone the whole grammatical mystery which has engaged Chomsky and others in our lifetime and linguists for time out of mind? No, the existence of language is one of the many phenomena – of which love and music are the two strongest – which suggest that human beings are very much more than collections of meat.

It seems to me that Wilson’s remarks contain a lot of good sense. Language really is a miracle, which cannot be explained from the bottom up, naturally.

What do readers think?