Humans Are Unique: Rats Are Unique

 

Historically, humans were deemed to be unique because of their “special relationship with God”, as well as their overall place in the universe. Later, specific features of humans were singled out as being unique. This tradition has carried on until this day. The physicist James Trefil wrote a book called Are We Unique? in which he discusses this subject in what he deemed to be a scientific manner. (So much so that he was “fearful of seeing [his] book quoted approvingly in some fuzzy New Age publication”.) Perhaps surprisingly to some (i.e., because Trefil is a scientist), he does deem humans to be unique — indeed, uniquely unique. The following essay takes issue with some of Trefil’s arguments.

The physicist James Trefil doesn’t hide his emotions, concern and, well, bias when discussing human uniqueness. For example, he tells his readers that he’s

“worried about a very new kind of incursion on traditional human space, one that comes from the machines that human beings, using their cerebral cortices, have built”.

So at least human beings built the machines…That’s until the machines themselves can build other machines. The word “incursion” (as in “incursion on traditional human space”) is strong too.

Elsewhere, Trefil writes:

“Make no mistake, though. This isn’t going to be a cool, dispassionate examination of an intellectual problem. I desperately *want* to find a way out of this dilemma, and I intend to devote whatever scientific skills I’ve developed in my career to finding it.”

Trefil is honest in the passage above. Yet his book is more rational, argumentative and balanced than many others I’ve read on this subject.

Trefil named his book Are We Unique. His conclusion is that “we” are unique. The problem here is that the word “unique” isn’t very helpful in this context. Even Trefil seems to see the (or one) problem, if only implicitly. He tells his readers that

“there are many species that have evolved unique adaptations over the millennia — think of the Venus’s-flytrap and the bat’s sonar navigational system”.

Not only that, Trefil concludes: “Being unique doesn’t necessarily make you special!”

Some readers may be able to add their own species which have unique features. Indeed, as soon as you begin to think about this, it’s clear that literally every species has at least one unique feature. So perhaps there’s unique, and then there’s unique. That’s the route which Trefil goes down.

Trefil stresses that he’s keen to take a scientific approach to the subject of human uniqueness. So much so that he was “fear[ful] of seeing [his] book quoted approvingly in some fuzzy New Age publication”. This is like those New Agers and spiritual idealists who constantly quote the same small number of passages from Werner Heisenberg, Erwin Schrodinger, Max Planck, etc. to advance New Ageism and/or idealism.

Either Science or the Soul?

The problem for Trefil is something he paints as being an either/or choice. (He states this either/or choice in various places.) For example, take animals:

“Looking at the human-animal boundary, some people argue that we either have to give up trying to make a distinction or have to give up scientific inquiry and accept the existence of something like the soul.”

What about machines? -

“At the human-machine boundary, we face a similar dilemma: either accept that the brain is just a reproducible collection of neurons or posit some nonmaterial (and non investigable) entity.”

Trefil concludes:

“In both cases, the message seems to be the same. Either give up any notion of human uniqueness or give up doing science.”

Is this really an either/or choice? The language Trefil uses seems to make this choice a necessity. But that’s just it. His assumptions can be questioned.

For example, what does Trefil mean by “distinction” (as in “trying to make a distinction”)? Accepting distinctions between animals and human beings doesn’t seem to have the results Trefil cites. After all, a cow can be distinguished from a rat. So he actually means specific and important distinctions.

A similar point can be aimed at his statement “either accept that the brain is just a reproducible collection of neuron or…” The brain isn’t just a collection of neurons, and not even “evil materialists” believe that. That said, this may not matter too much to Trefil. That’s because even if a brain is more than just a collection of neurons, everything else about a brain may be reproducible too. Surely if the brain weren’t reproducible, at least in principle, then perhaps we would need to fall back on some “nonmaterial (noninvestigable) entity”. However, the difficulties with reproducibility may have nothing whatsoever to do with anything nonmaterial or soul-like.

In simple terms, it seems obvious that there is another choice here: to accept human uniqueness and still carry on doing science. This, of course, depends on the special cases of uniqueness Trefil refers to. Yet even here we needn’t fall back on religion and give up on science when it comes to trespassing on the human “soul”. This seems to be an option Trefil himself is pursuing.

Differences in Degree and Kind

Trefil believes that humans instantiate “differences in kind”, not just “differences in degree”. So it will help here to see an example of a difference in kind. Trefil tells us about a

“rather profound difference between the toolmaking involved in a chimp using a stick to gather termites and that involved in humans building a jet aircraft or a skyscraper”.

This is a difference of degree. Of course, it’s possible that after chimps first started to use sticks as tools, that trick probably didn’t advance or change much after that. When it comes to human beings, on the other hand, in the 19th century there were no jet aircrafts or skyscrapers, and in the 20th century there were. (There are many other examples like this dating back long before that.) We can shrink the timespan down and talk about the Internet. There was no Internet in the 1960s, yet in the 1990s millions of people were using it. That’s a timespan of less than forty years. So the many differences between chimps and humans aren’t being denied here. They’re just not a case of differences in kind.

Having said all that, some scientists, philosophers and commentators go too far in the opposite direction, as Trefil is keen to tell us. For example, Trefil tells his readers that

“[i]t has lately become fashionable among intellectuals to ignore ways in which humans are different from other living things and concentrate on the ways in which we are similar”.

In the passage above, Trefil implies a problem without noting it. That problem is that it’s just as easy to “concentrate on the ways in which we are similar” as to “ignore ways in which humans are different”. It can even be said that the same facts and data are being approached from two different angles. Perhaps these two different angles are chosen for reasons of prior ideological, political or religious bias.

So we could play this game. I could mention a way in which humans are the same as some/many animals. And readers could mention a way in which humans are different from some/many animals.

Chimps using sticks to collect termites was mentioned earlier. So it’s interesting that Trefil quotes a “fashionable intellectual”, Carl Sagan, stressing the similarities in the following passage:

“‘Philosophers and scientists confidently offer up traits said to be uniquely human, and apes casually knock them down — toppling the pretension that humans constitute some sort of biological aristocracy.’”

It’s certainly true that philosophers, scientists and religious people have confidently offered up many traits said to be uniquely human. (History will show people that.) Yet there’s also something about Sagan’s rhetoric that some readers may not care for. As it is, I don’t know if chimps using sticks as tools was on Sagan’s mind. And I don’t know that Trefil had Sagan in mind when he used the words “fashionable intellectuals”. Having said that, ten lines after using the words “fashionable intellectuals”, Trefil does quote Sagan.

The Human Cerebral Cortex

According to Trefil, the source of the special uniqueness of human beings is the cerebral cortex. This organ “provides the difference we seek”. So Trefil is upfront about seeking out human uniqueness. Indeed, the cerebral cortex must do that job because

“[e]verything else about us, from our skeletons to the innermost working of our cells, is similar (and sometimes identical) to the ordinary run of things in the animal kingdom”.

Thus, the special uniqueness of human beings all hinges on the cerebral cortex.

Trefil’s stress on the cerebral cortex is placed within the context of evolution. He believes that all of us should shout the following words:

“This is amazing! Something has happened here. These animals have found a new way to win at the evolutionary game — something no other species on the planet has developed.”

This is false. Other animals have “w[o]n the evolutionary game” too.

This claim doesn’t mean that other species have evolved traits which helped them survive longer. That’s because that too would be a purely evolutionary matter. Instead, this means that some species have used their brains to win the game in real time, not as a result of genetic changes. In other words, many species didn’t wait for evolution. Here are four examples:

Octopuses open jars, manipulate objects, and learn quickly.

Dolphins use sponges as tools when foraging.

Crows and ravens manufacture tools and solve multi-step problems.

Rats “laugh” when tickled, demonstrate empathy, display “metacognition”, etc. [The opening image includes a rat in a maze. Yet other animals can work their way out of a maze. Does this mean that rats aren’t unique in this respect? It must do if we interpret the word “unique” literally. ]

These non-evolutionary changes are examples in which individual intelligence or social learning occurs within a single lifetime.

One possible riposte here would be that these other species adapted in real time because evolution provided them with the means which allowed them to do so. They didn’t need to wait for evolutionary change because evolution had already provided them with what they needed. The problem here is that this can be applied to human beings too.

Thus, Trefil might well have meant quicker and more widespread real-time adaptation when it comes to human beings. Yet that can only be a matter of degree when compared to certain other species. After all, humans didn’t do that much adapting for a long time. For most of their existence, humans didn’t display the kind of widespread and rapid adaptive power we saw in the last 10,000 years, and especially the last few centuries.

As we’ve seen, Trefil places a lot of stress on the cerebral cortex. Yet human beings had cerebral cortexes 300,000 years ago.

The problem is that Trefil seems to be bowled over by the advances and widespread nature of humans winning the evolutionary game. And no one could deny that humans keep on winning against not only evolution, but also biology and the environment too. Yet this is hard to quantify in terms of humans being the only species winning against evolution.

How do still-existing “primitive” human cultures fit into Trefil’s claims? (Let’s not focus on the word “primitive” here.) Would he say the following? -In principle, they are just like us. But isn’t it a contingent possibility that the human species as a whole might have stayed culturally stuck, say, 200,000 years ago?

In a sense, Trefil may unknowingly be ruling out people with mental/cognitive disabilities, people who’ve never invented or created anything, etc. too. This is a similar scenario to Roger Penrose’s argument that understanding (or “seeing”) “Gödel truths” makes human beings unique. However, if you can’t understand that a Gödel truth is a truth, then does that mean that you’re not a good example of the unique species?

The seeing of Gödel truths doesn’t even apply to all mathematicians. (Only meta-mathematicians — i.e., not mathematicians - and mathematical logicians give any deep thought to Gödel truths.) Can Penrose escape this by using the following words? - In principle, all human beings could recognise Gödel truths. This isn’t something Penrose could know about every human being. (Oddly enough, Trefil mentions that Penrose has often responded to his critics. He cites the case when Penrose tackled “twenty objections” in “excruciating[]detail[]”)

When it comes to the comparisons between chimps and humans mentioned earlier, it’s perhaps inevitable that Trefil said that he didn’t

“see the day coming when a chimpanzee will be able to do a calculus problem or compose a symphony, no matter what training it gets”.

Here we see a problem mentioned a few moments ago. Not all human beings can deal with a calculus problem or compose a symphony. Could they do so “in principle”? I don’t really know because the words “in principle” need to be spelled out. In any case, what about those 200,000 years or so in which humans didn’t do calculus or compose symphonies? Could these early humans do these things in principle too? What about those human beings who could never do calculus or compose a symphony?

A Physicist on Consciousness and Emergence

 

Emergence and its relation to consciousness has been discussed in minute detail by many analytic philosophers. So it’s always interesting to read the point of view of a physicist on this subject. The (former) physicist in this case is James Trefil. However, in order to arrive at consciousness, Trefil firstly discusses the addition of a single grain of sand to a sandpile, and how that can cause an avalanche. That’s deemed to be an emergent property of the sandpile. In order to make sense of all this, though, we need to make the important distinction between epistemic emergence and ontological emergence.

Image by ChatGPT, under the prompts of the writer.

It’s not surprising that a scientist like James Trefil believes that emergence is no problem for science. Indeed, he believes that

“it is important to realize that by posing the question in terms of emergent properties, we are avoiding the necessity of having to go outside the realm of science to find an answer”.

So not only is emergence deemed not to be a problem for science: posing the question in terms of emergent properties actually helps science find answers. Where else would we go anyway? Even if there are new laws or properties to be discovered, it would still be science, not philosophy or religion, which discovered them.

Epistemic Emergence

One important distinction which has to me made here is between epistemic emergence and ontological emergence. (This distinction more or less captures the distinction made between weak emergence and strong emergence.) In basic terms, some systems are so complex that they display (or instantiate) properties which go beyond our present understanding. This is how Trefil puts it:

“[I]t might turn out that when you put a sufficiently complex system together, you will be unable to predict what its properties are in practice because the connection between the individual parts and the final behaviour is too complicated to know.”

This is a case of epistemic emergence. It’s also interesting to note that Trefil was discussing an artificial, rather than a biological, system. Yet this may be a difference that doesn’t matter too much in this particular debate. Trefil also focusses on prediction in that even an artificial system may display properties that its creators didn’t foresee. (In Trefil’s own words, “this one speaks primarily to the question of whether we could understand a complex machine once it was built”.) This may seem intuitively odd to many people in that they may expect the creators to know in advance all of their systems properties and behaviours. (These details may point to Large Language Models and AI entities generally displaying emergent properties and behaviours.)

The reproductive biologist Jack Cohen and the mathematician Ian Stewart broach the same subject of epistemic emergence from a slightly different angle. Their point is that reductionism may fail in certain cases. Cohen and Stewart (as quoted by Trefil) write:

“‘If we wish to use reductionist rules to explain and understand high level structures, then we have to follow [a] chain of deduction. If that chain becomes too long, our brains begin to lose track of the explanation, and it ceases to be one. This is how emergent phenomena arise.’”

Prima facie, it seems that Cohen and Stewart are talking about pure logic when they speak in terms of having to “follow a chain of deduction”. Surely there must be more to it than that.

Anyway, the epistemic angle is well characterised when they say that “[i]f the chain becomes too long, our brains begin to lose track of the explanation”. So nothing weird or spooky is happening here. It’s essentially about our cognitive limitations and why they lead to a lack of understanding. In that sense, new phenomena emerge as a result of our cognitive limitations.

All this raises an interesting possibility which Trefil himself latches onto. What about what Trefil calls a “Divine Calculator”? This would be “a being with sufficient calculational abilities” to tell us everything about the system deemed to have emergent properties. Does this assume it would all (or only) be a matter of mathematical calculation? (Earlier it was hinted that Cohen and Stewart saw it all in terms of deduction.)

A Grain of Sand, A Sandpile and an Avalanche

Does a sandpile instantiate emergent properties?

Yes!

This is Trefil on that subject:

“The more sand grains you pile on, the more complex the web of forces becomes. Eventually, you add one more grain of sand and an avalanche flows down the side of the pile. In other words, the avalanche is a behavior that shows up only when the web of forces reaches a certain level of complexity. If you have to have a million grains of sand before you see an avalanche, you don’t get one-millionth of an avalanche in a single grain of sand.”

It may seem odd to some readers that a sandpile can display emergent properties. These properties are only epistemically emergent — so not really odd at all. In this case, the addition of a single grain of sand to a sandpile causes the avalanche. This is what Trefil calls a “discontinuous change”. It’s discontinuous because the addition of a grain of sand before the final one didn’t cause an avalanche. This may seem mildly contradictory. On the one hand, Trefil stresses complexity, on the other hand, a single grain of sand makes all the difference… However, that single grain of sand was added to the already-existing complexity (or “web of forces”) of the sandpile.

The avalanche can be summed up this way:

one added grain of sand + the complexity of the sandpile = avalanche

Trefil states that “this pattern of successive discontinuous changes is common in natural systems”. He then offers readers another example of discontinuous change. Trefil cites the “many steps between smooth flow and full turbulence in the flow of water”.

Consciousness and Emergence

This essay asks about whether consciousness is emergent. Trefil takes an incredibly simple position on this. To him, it’s all about complexity. More relevantly, the more complex the brain became (in evolutionary terms), the more emergent properties arose. In Trefil’s own words:

“[I]f we build a collection of neurons, adding one neuron at a time, the system will go through a series of discontinuous jumps, each jump corresponding to a new kind of emergent property — a new ‘avalanche’ — characteristic of its new level of complexity.”

Put so simply, it’s hard to know why a process of simple addition would have such results. However, it’s not actually that simple. That’s because neurons in and of themselves are complex entities. Added to that are the myriad of interrelations between neurons, as well as the importance of neurochemistry and brain structure. Thus, it’s not simply about 1, then 1 + 1, then 1+1+1… We aren’t actually talking about numbers: we’re talking about neurons.

Now let’s compare a grain of sand to a neuron at an even lower level. In terms of a single neuron, it “can generate an action potential, of course, but in the absence of other neurons there is nothing to which that potential can be communicated”. A single grain of sand is even more basic than that… Yet it caused an avalanche.

All this leads to a more relevant conclusion. Trefil continues:

“The kinds of phenomena we refer to as consciousness and intelligence, in this picture, correspond to emergent properties at the higher levels of the cascade.”

The philosopher Mark A. Bedau has said that “the notion of weak emergence is metaphysically benign”. On the other hand, he puts the argument for suspicion of strong emergence when he wrote the following:

“Although strong emergence is logically possible, it is uncomfortably like magic. How does an irreducible but supervenient downward causal power arise, since by definition it cannot be due to the aggregation of the micro-level potentialities? Such causal powers would be quite unlike anything within our scientific ken. This not only indicates how they will discomfort reasonable forms of materialism. Their mysteriousness will only heighten the traditional worry that emergence entails illegitimately getting something from nothing.”

Let’s remind ourselves that weak emergence is doing the work of epistemic emergence, and strong emergence is doing the work of ontological emergence.

Being a philosopher and not a physicist, it’s perhaps not surprising that Bedau spots a problem which Trefil doesn’t even mention: downward causation. In terms of Trefil’s position, how do his emergent properties causally impact on lower-level properties? However, since Trefil’s position is only one of epistemic emergence, there’s no reason to believe that higher-level properties can’t causally impact on lower-level properties. This is only a problem if the higher-level properties are deemed to be “irreducible but supervenient”. Does that mean that they’re ontologically emergent too? Are they epistemically or ontologically irreducible? And what about supervenience? Doesn’t this notion hint even more strongly at ontological emergence?

Trefil ties his position on emergence and discontinuous changes to evolution’s role in the creation of consciousness and higher-level mental functions. He writes:

“If the appearance of Homo erectus corresponded to the collection of neurons we call the brain reaching the point where new emergent properties became evident, we can understand how such a sudden change could have occurred.”

Many people stress that evolution is a very slow process. Yet that’s not always the case. In the case of consciousness and other properties of human persons, it might well have been a case of discontinuous changes — sudden changes. How sudden is sudden? Well, in the case of the final grain of sand mentioned earlier, the change that was an avalanche was very sudden. So does this example pass over to evolution and the rise of consciousness?

Panpsychism and Complexity

One way of looking at emergence being a result of complexity is to think about the philosophical position of panpsychism. In panpsychism, consciousness (or experience) has little to do with complexity. That’s because panpsychists believe that consciousness exists all the way down the line. If everything is conscious to some degree, then complexity isn’t an issue at all. Indeed, the philosopher David Chalmers makes this explicit when he plays up simplicity and plays down complexity. For example, Chalmers writes that

“one wonders how relevant this whiff of complexity will ultimately be to the arguments about consciousness”.

Chalmers goes further when he says that

“[o]nce a model with five units, say, is to be regarded as a model of consciousness, surely a model with one unit will also yield some insight”.

Is one “unit” one neuron? One molecule? One atom?… One transistor?

Chalmers also makes what seems to be an obvious point (at least it seems obvious if one already accepts his information/experience link). He writes:

“Surely, somewhere on the continuum between systems with rich and complex conscious experience and systems with no experience at all, there are systems with simple conscious experience. A model with superposition of information seems to be more than we need — why, after all, should not the simplest cases involve information experienced discretely?”

Yes, panpsychists attempt to get rid of the problem of emergence, at least as it applies to consciousness or experience. In Chalmers’ picture, we don’t have emergence because each unit (or simple case) instantiates experience to some degree. Despite that, panpsychism still allows for radical differences between systems with simple conscious experience, and the conscious experience of human persons and animals. Yet if complexity isn’t important, then why do we have any differences whatsoever between simple conscious units and conscious complex systems? Is this another variation of the combination problem or what can be called the additive problem? After all, this is a case in which units of simple conscious experience are simply added together to create a complex conscious system.

Chalmers gives a biological (or “real life”) example of this phenomenon too when he writes the following:

“We might imagine a traumatized creature that is blind to every other distinction to which humans are normally sensitive, but which can still experience hot and cold. Despite the lack of superposition, this experience would still qualify as a phenomenology.”

What we have here is subtraction, rather than addition. This traumatized creature has had all its complex and/or varied conscious experiences destroyed to be left with only the ability to experience hot and cold. (We can work in the other direction and add units too.)

Despite all that, it does seem obvious that complexity matters. After all, many scientists and theorists have made a strong link between the complexity of the brain and consciousness. Chalmers himself acknowledges the (intuitive) appeal of complexity when he continues:

“After all, does it not seem that this rich superposition of information is an inessential element of consciousness?”

Chalmers then rejects this requirement for complexity.

If we return to the sandpile. We don’t need the individual grain of sand (or unit) to have (to use Trefil’s words) “one-millionth of an avalanche” somehow within it to make sense of the avalanche. All we need is complexity plus the addition of a single grain of sand. In that sense, the final grain of sand is just like all the others.

What about a single neuron?

To the panpsychist, one single neuron instantiates some degree of consciousness. (The “parts” of that single neuron do so too.) Thus, the addition of neurons to a brain never cause an avalanche because consciousness was there all along.