Basic Dimension
http://sexualreligion.blogspot.com/
Number Archive
Preface
Michael I Christie is a specialist on wildlife trapping and has great experience in fatal scenarios in which animals end up. From that background, he gives his opinion on Dinaledi Chamber, not as a cemetery but as a trap for Hominins fleeing for predators like leopards. Because of freely accessible publications in Elife a lot of other disciplines are able to comment on Homo naledi. This is important because scenarios from different disciplines can help to discover what really happened with Homo naledi, 300,000 years ago. So, please read his views with an open mind.
Article discussion:
Michael I Christie: The Homo naledi “Burials” are Highly Improbable
Global Journal of Archaeology & Anthropology:
Christie M I. The Homo naledi �Burials� are Highly Improbable. Glob J Arch & Anthropol. 2017; 2(3): 555586. DOI: 10.19080/GJAA.2017.02.555586
https://juniperpublishers.com/gjaa/pdf/GJAA.MS.ID.555586.pdf
Michael I Christie* Department of Zoologist, Santa Barbara, USA
Summary review:
The article contains some serious methodological shortcomings that prevents the burial hypothesis from being falsified. But the line of reasoning itself is legitimate and constructive, since these questions must be asked. This makes us not reject 'The predator-induced Trap Scenario hypothesis' and the 'The predator-induced slide trap hypothesis'.
Maybe there were incoming predators in the Rising Star Cave and maybe there was not always enough time left to shut off Dragon's Back Chamber from Superman's Crawl. Maybe, it is not impossible. Meanwhile we found a second cave (Lesedi Chamber) for which predation must work also. Anyway, we must be vigilant for alternative hypotheses of the found bodily remains in Dinaledi Chamber.
Not rejected hypotheses:
Several predators will follow prey into a cave and even into a narrow passages such as the Superman’s Crawl. The possibility of an attack by pack hunters (hunting in groups, BD) is relevant because a pack is more likely to persist on the hunt even if other members have secured a prey item in another area, whereas a leopard might not bother. Once in the middle chamber hominins have the possibility of climbing up Dragon’s Back. Early hominids lived most of their nights in total darkness and would be used to groping around in a tree, rock face or cave. Threatened by predator(s) on the hunt.
Even if the predators could not get to the middle chamber an alarm call or a screaming victim in the inner passages would send other members scampering up the walls, pushing back into every nook and cranny at the top of Dragon’s Back.
Predators drag carcass into caves and leave the remains, but a predator is not likely to drag a carcass up Dragon’s Back and down a narrow shaft, granted. But all this only considers predation after the prey has been killed. Predators would very likely chase potential prey deep into a cave if the prey escapes into the cave or they wandered in and surprised prey already in the cave. Leopard, hyena, and even lions are likely candidates.
Article discussion:
Michael I Christie: The Homo naledi “Burials” are Highly Improbable
https://juniperpublishers.com/gjaa/pdf/GJAA.MS.ID.555586.pdf
Abstract
In 2015 the discoverers of Homo naledi in the Dinaledi Chamber of the Rising Star Cave of South Africa proposed ‘Deliberate Disposal’ (i.e. burial) as the best explanation for this uniquely rich monospecific trauma-free fossil deposit. Due to the small brain size and other primitive features of this new species, the proposed ‘cultural’ explanation was met with considerable skepticism, practical difficulties were soon pointed out and other possibilities proposed, but due to lack of dating and other details the issue remained unresolved. Concrete dating of the fossils and additional information published recently by the same team has led them to reaffirm the ‘cultural’ hypotheses in three separate papers, but the evidence is still unconvincing. In fact, several of the conditions the authors claim to be evidence for burial are shown to argue against this option. Alternative ‘natural’ mechanisms are proposed, evaluated and estimated to be significantly less improbable than the burial hypothesis.
Michael I Christie: Comments on the six original hypothesis considered by Dirks et al.[2]
'Cognitive issues are not considered. I assume an overall premise that natural explanations are more parsimonious that those (than cultural explanations, BD) requiring intentional, deliberate intervention of any kind.'
Michael I Christie: The Homo naledi “Burials” are Highly Improbable
“We welcome alternative scenarios that explain the data, but they must explain all the data” [3]. For a data set as complex and multidimensional as this, that is a pretty tall order. Anyway, here we go.
Our reaction on this article:
Michael I Christie:
Comments on the six original hypothesis considered by Dirks et al.[2]
'Cognitive issues are not considered. I assume an overall premise that natural explanations are more parsimonious that those (than cultural explanations, BD) requiring intentional, deliberate intervention of any kind.'
'Conversely, no cognitive assumptions are necessary for random ‘maze’ accidents including predator or water induced trap scenarios, so these ideas seem to be much less problematic'.
Our comment:
This comes down to circular reasoning, to start a scientific review with the a priori exclusion of cultural explanations to conclude to natural causes. The principal fallacy of thinking is that 'parsimony' (read: investigator bias) will lead to the truth. We give the occupation hypothesis and the predator hypotheses a real chance in the discussion.
The second fallacy is the suggestion that statistical more likely events will take us to the truth. That is not what Ockham meant with his razor. BTW, the statistical substance of natural causes is mentioned but not given or is rather shaky.
Homo naledi was not directly comparable with baboons
Of course, we also adhere Ockham's razor and are inclined to simplify the Dinaledi Chamber scenario where possible. But Ockham's razor must remain within the prevailing state of nature, within the intellectual domain of Homo naledi, who was not an animal but a well developed bipedal Hominin.
Ockham's razor is misused if equating baboons (quadrupeds) with Homo naledi (bipeds directly. We must stick to the mental abilities of Homo naledi. So if Homo naledi was able to make ropes, then why would not they use them in the Rising Star Cave?
Parsimony is only admitted for comparison of corresponding domains. That is the flaw in above article. The intellectual domain from baboons is not the same as from Homo naledi. They used fundamentally different strategies. Therefore, they can not simply be compared.
Baboons are highly intelligent quadrupeds but intellectually uncomparable with bipedal primates. Quadrupeds simply missed the bipedal creativity mutation with the intellectual paradigm shift, seven million years ago. Homo naledi bypassed simple solutions (3D-mapping of the cave in the dark) by the more inventive and creative strategy of laying grass cords:
As an example, baboons found a rope hanging into a pit, but bipedal primates discovered grass ropes already seven million years ago. Grass cables are the sufficient condition for mastering the Rising Star Cave, wiping out all lower order strategies like feeling blindly routes through the cave. Also echolocation like bats and using fire became obsolete.
So, Homo Naledi would simply lower a grass cord into the pit of the baboons. Just like he would have done in the Chute in case an infant had fallen into Dinaledi Chamber.
In concluding:
1) in principle, there is no scientific difference between natural and cultural explanations. In the end, deliberate disposal of the dead is also based on naturally founded behavior.
2) Furthermore, deliberate intervention can be the most parsimonious choice to understand the situation of Dinaledi Chamber. For, bipeds have a fundamentally different behavioral domain than quadrupeds.
Bipeds and quadrupeds
In the evolution bipeds developed smaller canines while they just lived more and more in the open plains devoid of trees. We just would expect them to develop bigger canines, just like baboons. Of course there are a lot of reasons why they did not. But remember, smaller canines were only possible because they could defend themselves more efficiently than baboons. So bipeds must have developed a completely different defense strategy against predators from the beginning. Without the use of spears and grass ropes, they would never have been able to leave the forests.
Great apes are not as fertile as baboons. Baboons have very dangerous canines and in groups they can chase away leopards in daytime. They also develop a reasonable speed to escape from predators.
But bipeds did not have many offspring and so were not that numerous. They were also slow long distance runners which could not defend themselves against predators without weapons. Without wooden spears they would be completely defenseless in the open plains and extinct in no time. But they survived for seven million years. How come?
The conclusion is that we can not compare baboons with Homo naledi directly.
Homo naledi was a rational thinker
Of course, we have also our doubtful assumptions, but the difference is they are scientifically based. We think Australopiths were not as stupid as always thought. They must have invented spears and grass cables when still high in the trees. Only then they could roam into the savannas and defend themselves against predators over seven million years.
So, apparently they had a really rational brain to survive in situations where we would fail with our magical cauliflower brain. And it is very probable that they already had the blueprint of our brain, though, of course, they did not believe in the soul:
The healthy brain of Australopithecus
The Lunate Sulcus by Ralph Holloway
Ralph Holloway is an endocast specialist who studies the inside skull to determine brain development of hominins. He also investigated the skull of Salam (3.3 Ma; 400cc; Ethiopia) and discovered the three years old child's brain was already rewired and different from chimps. The lunate sulcus marking vision structures had moved back on the skull making place for a larger neo cortex. So Salam was already more intelligent than chimps with 400cc brains:
Highly intelligent monkeys
Homo naledi was a very intelligent Hominin and would have blocked Superman's Crawl at nights from the Dragon's Back Chamber side, to prevent leopards from coming in and to prevent panic flights into the Chute. If there lie no stones they did not use the cave as a refuge. Maybe only in panicked situations. If they used stones, there must be scratches on the wall from Superman's Crawl and they possibly attacked incoming leopards:
Baboons only fled into their cave because leopards could not get out. But predators simply walked into the Rising Star Cave. So Homo naledi was not on the run for predators. Maybe only in panicked situations. He was also not on the run for Homo erectus and hiding in Dragon's Back Chamber. Since, Homo erectus could simply block Superman's Crawl what would be the end of Homo naledi.
If Homo naledi wanted to escape from other Hominins into the Rising Star Cave, then there had to be escape possibilities, exits on the other side of the cave. There are only two entrances next to each other. Totally unreliable refuge:
We conclude, Homo naledi never used the Rising Star Cave as a refuge on a regular base. We skip this scenario and upgrade to attributed mental abilities of Homo naledi. Then we automatically arrive at burials.
Michael I Christie:
'The first item that needs revision is the no occupation assumption, and the associated idea that deep exploration of the cave required fires or torches and so on.'
Our comment:
We maintain the 'no occupation assumption' because living in the cave is very impractical and rather senseless as defense. And we have also rejected fire or torches as they are unnecessary and complementary tools to grass cables.
Michael I Christie:
'As mentioned, BBC Earth has recently released the documentary “Monkey Planet” the first Episode of which includes one story on Chacma Baboons in South Africa’s Cape area that use a deep cave as a sleeping refuge.'
Our comment:
- We reject the Rising Star Cave as sleeping refuge, because it is impractical and totally dangerous, for, predators could enter into Dragon's Back Chamber easily and Homo erectus could block Superman's Crawl from the outside on which they would be trapped. It could have functioned as such only in panicked situations.
- If Homo naledi wanted to escape into the Rising Star Cave for other Hominins, then there had to be escape possibilities, exits on the other side of the cave. There are only two entrances next to each other. Totally unreliable refuge.
- In theory Homo naledi could have used the Dragon's Back Chamber as a refuge against predators and have barricaded the Crawl from the Dragon inside. But then we would expect a lot of stones in Dragon's Back Chamber for defense against predators. Then there must also be scratches on the walls of the Crawl.
Ropes
Baboons used a rope laid by humans. Because they missed the paradigm shift they were unable to invent ropes by themselves. They found their way a hundred meters far into the cave. I do not know how many distracting tunnels there are in that cave. If not they even do not need 3D-representation.
But it seems they can be lost in that cave, though...they found only one skull. Has the animal fallen into the cave before the rope hung? Time dating of the skull?
Michael I Christie:
Signs of habitual use are everywhere, including at least one baboon skull and many bones scattered on the floor (the cave surely also acts as a pitfall trap). This natural experiment looks as if designed to shed light on the alternatives discussed here.
Our comment:
Maybe baboons would not find their way in the Rising Star Cave. Let's do an experiment with a tame exemplar. But I would prefer chimps, or better bonobos. BTW, one baboon tooth is found in Dinaledi Chamber from 800 ka ago.
3D-mapping for primates
We also adhere the 3D-mapping presumption in our scenarios and expect Homo naledi having used his 3D-compass in the cave, as we suppose Australopiths used 3D-orientation for sleeping in trees at nights.
Experts tell us that apes and monkeys see badly at nights. Maybe that is why they need 3D-mapping.
But 3D mapping is not a necessary assumption to the Dinaledi scenario any longer, because we assume Homo naledi was able to make grass ropes. Then, Homo naledi did not need this quality of baboons, but we still think they were able to.
Here we see Ockham's razor misused, because Homo naledi needed no 3D-mapping at all, for he invented ropes and sticks and spears already 7 million years earlier. The grass-cable assumption is a sufficient condition for routing through the cave.
If 3D-mapping from caves is possible for apes, which are sleeping in trees at nights, then they do not need echolocation, storing cave maps into their brains directly. But echolocation has already been degraded to a complementary tool in our grass cable scenario and is not really needed any longer.
- Here we see Ockham's razor misused, because Homo naledi needed no 3D-mapping at all, for he invented ropes and sticks and spears already 7 million years earlier. The grass-cable assumption is a sufficient condition for routing through The Rising Star Cave.
- The problem with above article is that the 'most parsimonious' solution places Homo naledi alongside monkeys, while they actually belong more to humans. Then the state of nature from Homo naledi is denied. This is the wrong use of the principle of parsimony and an unreasonable flight into 'natural' causes.
- So, because we assume grass cables as sufficient condition to reach Dinaledi Chamber, we can skip 3D-mapping, echolocation and fire.
- We do not expect elderly people and toddlers climbing haphazardly on Dragon's Back and falling into Dinaledi Chamber. The age structure of the bodily remains shows a cemetery. And in case of danger they simply would block the Chute. Because, if they did not believe in a cemetery, why would they let this hole open? Maybe because they could not drag big stones through Superman's Crawl.
ADDENDUM
Michael I Christie:
The flood-induced Trap Scenario
After the discovery was reported, a number of questions still remained. These questions included: why were so many fossils from a single species found at the one site, and how did they come to rest so far into the cave system? Possible explanations such as H. naledi living in the cave or being washed in by a flood were considered but ruled out. Instead, the evidence was largely consistent with intact bodies being deliberately disposed of in the cave and then decomposing.
Michael I Christie:
A question of improbabilities
The physical difficulty of hauling corpses in is so obvious it is one of the most cited objections. Again, lack of trauma in such a large sample strongly argues against the notion that the individuals died prior to reaching the chamber. It is inconceivable
that over countless cases nobody ever dropped a body as they were struggling in the dark with a heavy load up Dragon’s Back, about 11 meters or 7 erect “naledi” high (Figure 2). To illustrate, if the probability of hauling one body in without a scratch is say 85%, then the probability of succeeding with over a dozen is less than 12%. That assumes of course that none of the bodies had suffered perimortem bone-trauma, highly unlikely in the harsh african environment [11]. If 75% of deaths are bone-trauma free the likelihood of hauling 13 intact skeletons into the chamber in a row drops below 1%. If p is lower than 50%, the end odds shrink to less than 1/10,000.
The lack of bone-trauma has been stressed as being so low that the most reasonable explanation is that these individuals died inside the Dinaledi Chamber in a way that was non-traumatic to bones. So the problem is more a question of how and why they
got there alive and uninjured. A natural explanation demands a very species-specific trap as described above or some other passive mechanism.
Our comment:
Michael, many thanks for this most interesting explanation. It is all possible, really, but 100 ka is a long period and we only need some contiguous generations, and there may have been a dry period and BTW, corpses might have been damaged by transport but not the bones broken. And they weighted only 40 kg, that's not too much. It is not all statistics in life. We must add the interaction of the attributed intellect from Homo naledi to the scenarios. And by religion, humans and probably also Homo naledi, have done the most weird things you can imagine.
.jpg)
http://sexualreligion.blogspot.com/
Number Archive
Preface
Michael I Christie is a specialist on wildlife trapping and has great experience in fatal scenarios in which animals end up. From that background, he gives his opinion on Dinaledi Chamber, not as a cemetery but as a trap for Hominins fleeing for predators like leopards. Because of freely accessible publications in Elife a lot of other disciplines are able to comment on Homo naledi. This is important because scenarios from different disciplines can help to discover what really happened with Homo naledi, 300,000 years ago. So, please read his views with an open mind.
Article discussion:
Michael I Christie: The Homo naledi “Burials” are Highly Improbable
Global Journal of Archaeology & Anthropology:
Christie M I. The Homo naledi �Burials� are Highly Improbable. Glob J Arch & Anthropol. 2017; 2(3): 555586. DOI: 10.19080/GJAA.2017.02.555586
https://juniperpublishers.com/gjaa/pdf/GJAA.MS.ID.555586.pdf
Michael I Christie* Department of Zoologist, Santa Barbara, USA
Summary review:
The article contains some serious methodological shortcomings that prevents the burial hypothesis from being falsified. But the line of reasoning itself is legitimate and constructive, since these questions must be asked. This makes us not reject 'The predator-induced Trap Scenario hypothesis' and the 'The predator-induced slide trap hypothesis'.
Maybe there were incoming predators in the Rising Star Cave and maybe there was not always enough time left to shut off Dragon's Back Chamber from Superman's Crawl. Maybe, it is not impossible. Meanwhile we found a second cave (Lesedi Chamber) for which predation must work also. Anyway, we must be vigilant for alternative hypotheses of the found bodily remains in Dinaledi Chamber.
Not rejected hypotheses:
Michael I Christie:
The predator-induced Trap ScenarioSeveral predators will follow prey into a cave and even into a narrow passages such as the Superman’s Crawl. The possibility of an attack by pack hunters (hunting in groups, BD) is relevant because a pack is more likely to persist on the hunt even if other members have secured a prey item in another area, whereas a leopard might not bother. Once in the middle chamber hominins have the possibility of climbing up Dragon’s Back. Early hominids lived most of their nights in total darkness and would be used to groping around in a tree, rock face or cave. Threatened by predator(s) on the hunt.
Even if the predators could not get to the middle chamber an alarm call or a screaming victim in the inner passages would send other members scampering up the walls, pushing back into every nook and cranny at the top of Dragon’s Back.
This is precisely the situation described by Steven Tucker and Rick Hunter that lead them into the chute that leads to the lower chamber, and to their discovery of the Dinaledi Chamber and the fossils. They might then slip down, particularly a scared infant or youngster, plus the mother attempting reaching it, till it drops into the lower chamber. Once in the Dinaledi Chamber it would be doomed, particularly if it was filled with water they’d hardly have a choice.
Michael I Christie:
The predator-induced slide trap hypothesis
Predators drag carcass into caves and leave the remains, but a predator is not likely to drag a carcass up Dragon’s Back and down a narrow shaft, granted. But all this only considers predation after the prey has been killed. Predators would very likely chase potential prey deep into a cave if the prey escapes into the cave or they wandered in and surprised prey already in the cave. Leopard, hyena, and even lions are likely candidates.
So could the peculiar layout of the Rising Star Cave act as a species-specific predator-induced trap for hominins? The obvious candidate for the Dinaledi Chamber is to consider it a slide trap (typified by the antlion’s cone pits). In a nutshell: moving deep into the cave to escape predators, hominins clambered up the Dragon’s Back, crammed at the top and occasionally into the chute, where some slipped down and ended up trapped in the Dinaledi Chamber. '
Article discussion:
Michael I Christie: The Homo naledi “Burials” are Highly Improbable
https://juniperpublishers.com/gjaa/pdf/GJAA.MS.ID.555586.pdf
Abstract
In 2015 the discoverers of Homo naledi in the Dinaledi Chamber of the Rising Star Cave of South Africa proposed ‘Deliberate Disposal’ (i.e. burial) as the best explanation for this uniquely rich monospecific trauma-free fossil deposit. Due to the small brain size and other primitive features of this new species, the proposed ‘cultural’ explanation was met with considerable skepticism, practical difficulties were soon pointed out and other possibilities proposed, but due to lack of dating and other details the issue remained unresolved. Concrete dating of the fossils and additional information published recently by the same team has led them to reaffirm the ‘cultural’ hypotheses in three separate papers, but the evidence is still unconvincing. In fact, several of the conditions the authors claim to be evidence for burial are shown to argue against this option. Alternative ‘natural’ mechanisms are proposed, evaluated and estimated to be significantly less improbable than the burial hypothesis.
Michael I Christie: Comments on the six original hypothesis considered by Dirks et al.[2]
'Cognitive issues are not considered. I assume an overall premise that natural explanations are more parsimonious that those (than cultural explanations, BD) requiring intentional, deliberate intervention of any kind.'
Michael I Christie: The Homo naledi “Burials” are Highly Improbable
Alternative scenarios
“We welcome alternative scenarios that explain the data, but they must explain all the data” [3]. For a data set as complex and multidimensional as this, that is a pretty tall order. Anyway, here we go.
The first item that needs revision is the no occupation assumption, and the associated idea that deep exploration of the cave required fires or torches and so on.
An impertinent troop of cave dwelling Chacma Baboon (Papio ursinus) has proved us all wrong. As mentioned, BBC Earth has recently released the documentary
“Monkey Planet” the first Episode of which includes one story on Chacma Baboons in South Africa’s Cape area that use a deep cave as a sleeping refuge.
This case could hardly be more relevant to this discussion. The troop lives and forages on a very windy exposed coastal area almost devoid of trees, but the greatest threat comes from leopard predation at night. The troop has discovered a cave system accessed by a small hole in the ground and an eight meter vertical drop. According to the commentator, Dr. George Mc Gavin, the cave has probably become accessible to them recently, via a rope left dangling from the outer lip to the pit’s floor by a bat research team time ago. The baboons rappel into the pit at dusk and feel their way about, up to 100 m into the cave system in pitch darkness, where they sleep. They seem to have a mental map of the cave.
“Monkey Planet” the first Episode of which includes one story on Chacma Baboons in South Africa’s Cape area that use a deep cave as a sleeping refuge.
This case could hardly be more relevant to this discussion. The troop lives and forages on a very windy exposed coastal area almost devoid of trees, but the greatest threat comes from leopard predation at night. The troop has discovered a cave system accessed by a small hole in the ground and an eight meter vertical drop. According to the commentator, Dr. George Mc Gavin, the cave has probably become accessible to them recently, via a rope left dangling from the outer lip to the pit’s floor by a bat research team time ago. The baboons rappel into the pit at dusk and feel their way about, up to 100 m into the cave system in pitch darkness, where they sleep. They seem to have a mental map of the cave.
Signs of habitual use are everywhere, including at least one baboon skull and many bones scattered on the floor (the cave surely also acts as a pitfall trap). This natural experiment looks as if designed to shed light on the alternatives discussed here.
It’s very existence demonstrates that monkeys, and presumably hominids, will take advantage of any situation that becomes available, will penetrate deep into the dark zone of a cave system without the need for torches or any other ‘cultural’ accessories, and will die in the cave in the absence of predation.
It’s very existence demonstrates that monkeys, and presumably hominids, will take advantage of any situation that becomes available, will penetrate deep into the dark zone of a cave system without the need for torches or any other ‘cultural’ accessories, and will die in the cave in the absence of predation.
A similar situation could easily have developed in the Rising Star system. If a troop periodically slept in Dragon’s Back Chamber the probability of individuals occasionally stumbling into the Dinaledi Chamber’s chute increases exponentially.
Over the thousands of years involved fifteen such ‘accidents’, or even fifty, could easily occur. If this were correct no other explanation would be needed, but this might not satisfy everybody so let’s consider other alternatives.
Discussion
Over the thousands of years involved fifteen such ‘accidents’, or even fifty, could easily occur. If this were correct no other explanation would be needed, but this might not satisfy everybody so let’s consider other alternatives.
Discussion
The Disposal Hypothesis is appealing in many ways. Associating early hominin evolution with caves, self conscious development and burials all seems fitting. But deliberate disposal also implies all sorts of practical skills and cognitive abilities, shared intentionality and much focused determination! The practical and statistical improbabilities also detract from the viability of the hypothesis.
Adding the problems derived from the time span of the deposits, in my opinion it all makes this alternative highly improbable.
Conversely, no cognitive assumptions are necessary for random ‘maze’ accidents including predator or water induced trap scenarios, so these ideas seem to be much less problematic.
Thus these ‘natural’ mechanisms can explain most of the data and are not affected by the improbabilities surrounding the lack of trauma in the fossil remains. This alone makes it at least a couple orders of magnitude less improbable than the disposal hypothesis and the overall difference may well be much much larger.
Also, as as shown above, the probability of random accidents is additive over time so, given enough time, they become a virtual certainty. Since the time spans are huge, cumulative accidents are a viable answer to the Dinaledi mystery in particular."
---------------------------------------
Our reaction on this article:
Michael I Christie:
Comments on the six original hypothesis considered by Dirks et al.[2]
'Cognitive issues are not considered. I assume an overall premise that natural explanations are more parsimonious that those (than cultural explanations, BD) requiring intentional, deliberate intervention of any kind.'
'Conversely, no cognitive assumptions are necessary for random ‘maze’ accidents including predator or water induced trap scenarios, so these ideas seem to be much less problematic'.
Our comment:
This comes down to circular reasoning, to start a scientific review with the a priori exclusion of cultural explanations to conclude to natural causes. The principal fallacy of thinking is that 'parsimony' (read: investigator bias) will lead to the truth. We give the occupation hypothesis and the predator hypotheses a real chance in the discussion.
The second fallacy is the suggestion that statistical more likely events will take us to the truth. That is not what Ockham meant with his razor. BTW, the statistical substance of natural causes is mentioned but not given or is rather shaky.
Homo naledi was not directly comparable with baboons
Of course, we also adhere Ockham's razor and are inclined to simplify the Dinaledi Chamber scenario where possible. But Ockham's razor must remain within the prevailing state of nature, within the intellectual domain of Homo naledi, who was not an animal but a well developed bipedal Hominin.
Ockham's razor is misused if equating baboons (quadrupeds) with Homo naledi (bipeds directly. We must stick to the mental abilities of Homo naledi. So if Homo naledi was able to make ropes, then why would not they use them in the Rising Star Cave?
Parsimony is only admitted for comparison of corresponding domains. That is the flaw in above article. The intellectual domain from baboons is not the same as from Homo naledi. They used fundamentally different strategies. Therefore, they can not simply be compared.
Baboons are highly intelligent quadrupeds but intellectually uncomparable with bipedal primates. Quadrupeds simply missed the bipedal creativity mutation with the intellectual paradigm shift, seven million years ago. Homo naledi bypassed simple solutions (3D-mapping of the cave in the dark) by the more inventive and creative strategy of laying grass cords:
As an example, baboons found a rope hanging into a pit, but bipedal primates discovered grass ropes already seven million years ago. Grass cables are the sufficient condition for mastering the Rising Star Cave, wiping out all lower order strategies like feeling blindly routes through the cave. Also echolocation like bats and using fire became obsolete.
So, Homo Naledi would simply lower a grass cord into the pit of the baboons. Just like he would have done in the Chute in case an infant had fallen into Dinaledi Chamber.
In concluding:
1) in principle, there is no scientific difference between natural and cultural explanations. In the end, deliberate disposal of the dead is also based on naturally founded behavior.
2) Furthermore, deliberate intervention can be the most parsimonious choice to understand the situation of Dinaledi Chamber. For, bipeds have a fundamentally different behavioral domain than quadrupeds.
Bipeds and quadrupeds
In the evolution bipeds developed smaller canines while they just lived more and more in the open plains devoid of trees. We just would expect them to develop bigger canines, just like baboons. Of course there are a lot of reasons why they did not. But remember, smaller canines were only possible because they could defend themselves more efficiently than baboons. So bipeds must have developed a completely different defense strategy against predators from the beginning. Without the use of spears and grass ropes, they would never have been able to leave the forests.
Great apes are not as fertile as baboons. Baboons have very dangerous canines and in groups they can chase away leopards in daytime. They also develop a reasonable speed to escape from predators.
But bipeds did not have many offspring and so were not that numerous. They were also slow long distance runners which could not defend themselves against predators without weapons. Without wooden spears they would be completely defenseless in the open plains and extinct in no time. But they survived for seven million years. How come?
Homo naledi was a rational thinker
Of course, we have also our doubtful assumptions, but the difference is they are scientifically based. We think Australopiths were not as stupid as always thought. They must have invented spears and grass cables when still high in the trees. Only then they could roam into the savannas and defend themselves against predators over seven million years.
Assumption 374: A necessary condition for bipedality was spear defense. Bipedal primates did not exchange the forests for the savannas without this simple and effective protection against predators. Spears were not invented but arose naturally from their environment. Australopiths must have transported multiple spears tied together with ropes from knotted grasses. Knots that they did not invent, but that originated naturally and were learned to untie. First bipeds themselves invented nothing, no stone tools, but wooden tools came on their way.
So, apparently they had a really rational brain to survive in situations where we would fail with our magical cauliflower brain. And it is very probable that they already had the blueprint of our brain, though, of course, they did not believe in the soul:
The healthy brain of Australopithecus
The Lunate Sulcus by Ralph Holloway
Ralph Holloway is an endocast specialist who studies the inside skull to determine brain development of hominins. He also investigated the skull of Salam (3.3 Ma; 400cc; Ethiopia) and discovered the three years old child's brain was already rewired and different from chimps. The lunate sulcus marking vision structures had moved back on the skull making place for a larger neo cortex. So Salam was already more intelligent than chimps with 400cc brains:
Homo naledi was a very intelligent Hominin and would have blocked Superman's Crawl at nights from the Dragon's Back Chamber side, to prevent leopards from coming in and to prevent panic flights into the Chute. If there lie no stones they did not use the cave as a refuge. Maybe only in panicked situations. If they used stones, there must be scratches on the wall from Superman's Crawl and they possibly attacked incoming leopards:
Baboon cave for the night in Ethiopia
The Rising Star Cave was not suitable as refuge
Baboons only fled into their cave because leopards could not get out. But predators simply walked into the Rising Star Cave. So Homo naledi was not on the run for predators. Maybe only in panicked situations. He was also not on the run for Homo erectus and hiding in Dragon's Back Chamber. Since, Homo erectus could simply block Superman's Crawl what would be the end of Homo naledi.
If Homo naledi wanted to escape from other Hominins into the Rising Star Cave, then there had to be escape possibilities, exits on the other side of the cave. There are only two entrances next to each other. Totally unreliable refuge:
We conclude, Homo naledi never used the Rising Star Cave as a refuge on a regular base. We skip this scenario and upgrade to attributed mental abilities of Homo naledi. Then we automatically arrive at burials.
Michael I Christie:
'The first item that needs revision is the no occupation assumption, and the associated idea that deep exploration of the cave required fires or torches and so on.'
Our comment:
We maintain the 'no occupation assumption' because living in the cave is very impractical and rather senseless as defense. And we have also rejected fire or torches as they are unnecessary and complementary tools to grass cables.
Michael I Christie:
'As mentioned, BBC Earth has recently released the documentary “Monkey Planet” the first Episode of which includes one story on Chacma Baboons in South Africa’s Cape area that use a deep cave as a sleeping refuge.'
Our comment:
- We reject the Rising Star Cave as sleeping refuge, because it is impractical and totally dangerous, for, predators could enter into Dragon's Back Chamber easily and Homo erectus could block Superman's Crawl from the outside on which they would be trapped. It could have functioned as such only in panicked situations.
- If Homo naledi wanted to escape into the Rising Star Cave for other Hominins, then there had to be escape possibilities, exits on the other side of the cave. There are only two entrances next to each other. Totally unreliable refuge.
Ropes
Baboons used a rope laid by humans. Because they missed the paradigm shift they were unable to invent ropes by themselves. They found their way a hundred meters far into the cave. I do not know how many distracting tunnels there are in that cave. If not they even do not need 3D-representation.
But it seems they can be lost in that cave, though...they found only one skull. Has the animal fallen into the cave before the rope hung? Time dating of the skull?
Michael I Christie:
Signs of habitual use are everywhere, including at least one baboon skull and many bones scattered on the floor (the cave surely also acts as a pitfall trap). This natural experiment looks as if designed to shed light on the alternatives discussed here.
Our comment:
Maybe baboons would not find their way in the Rising Star Cave. Let's do an experiment with a tame exemplar. But I would prefer chimps, or better bonobos. BTW, one baboon tooth is found in Dinaledi Chamber from 800 ka ago.
3D-mapping for primates
We also adhere the 3D-mapping presumption in our scenarios and expect Homo naledi having used his 3D-compass in the cave, as we suppose Australopiths used 3D-orientation for sleeping in trees at nights.
Experts tell us that apes and monkeys see badly at nights. Maybe that is why they need 3D-mapping.
But 3D mapping is not a necessary assumption to the Dinaledi scenario any longer, because we assume Homo naledi was able to make grass ropes. Then, Homo naledi did not need this quality of baboons, but we still think they were able to.
Here we see Ockham's razor misused, because Homo naledi needed no 3D-mapping at all, for he invented ropes and sticks and spears already 7 million years earlier. The grass-cable assumption is a sufficient condition for routing through the cave.
If 3D-mapping from caves is possible for apes, which are sleeping in trees at nights, then they do not need echolocation, storing cave maps into their brains directly. But echolocation has already been degraded to a complementary tool in our grass cable scenario and is not really needed any longer.
The problem with above article is that the 'most parsimonious' solution places Homo naledi alongside monkeys, while they actually belong more to humans. Then the state of nature from Homo naledi is denied. This is the wrong use of the principle of parsimony.
So, because we assume grass cables as sufficient condition to reach Dinaledi Chamber, we can skip 3D-mapping, echolocation and fire.
Michael I Christie:
'It’s very existence demonstrates that monkeys, and presumably hominids, will take advantage of any situation that becomes available, will penetrate deep into the dark zone of a cave system without the need for torches or any other ‘cultural’ accessories, and will die in the cave in the absence of predation.'
Our comment:
So, because we assume grass cables as sufficient condition to reach Dinaledi Chamber, we can skip 3D-mapping, echolocation and fire.
Michael I Christie:
'It’s very existence demonstrates that monkeys, and presumably hominids, will take advantage of any situation that becomes available, will penetrate deep into the dark zone of a cave system without the need for torches or any other ‘cultural’ accessories, and will die in the cave in the absence of predation.'
Our comment:
This is a meaningless statement. All living beings will take advantage of any situation that becomes available, that is just 'survival of the fittest'. In our scenario torches are but complementary tools to grass cables. Homo naledi likely died outside the cave in the absence of predation.
Michael I Christie:
'If a troop periodically slept in Dragon’s Back Chamber the probability of individuals occasionally stumbling into the Dinaledi Chamber’s chute increases exponentially. Over the thousands of years involved fifteen such ‘accidents’, or even fifty, could easily occur.'
Our comment:
We do not expect elderly Hominins and toddlers climbing haphazardly on Dragon's Back and falling into Dinaledi Chamber. Yet, the age structure of the bodily remains shows a cemetery. And in case of danger Homo naledi simply would block the Chute. Because, if they did not believe in a cemetery, why would they let this hole open with exponentially increasing accidents? But possibly they could not drag big stones through Superman's Crawl.
Victims in need would be hoisted from Dinaledi Chamber into Dragon's Back Chamber with grass cables. Because, then it was no 'rebirth without soul', but an accident of a loved one. Hence, Homo naledi would descend into Dinaledi chamber. Also in case of monkeys, no fallen babies would be left in Dinaledi Chamber:
https://www.youtube.com/watch?v=xg79mkbNaTg
Michael I Christie:
Michael I Christie:
'If a troop periodically slept in Dragon’s Back Chamber the probability of individuals occasionally stumbling into the Dinaledi Chamber’s chute increases exponentially. Over the thousands of years involved fifteen such ‘accidents’, or even fifty, could easily occur.'
Our comment:
We do not expect elderly Hominins and toddlers climbing haphazardly on Dragon's Back and falling into Dinaledi Chamber. Yet, the age structure of the bodily remains shows a cemetery. And in case of danger Homo naledi simply would block the Chute. Because, if they did not believe in a cemetery, why would they let this hole open with exponentially increasing accidents? But possibly they could not drag big stones through Superman's Crawl.
Victims in need would be hoisted from Dinaledi Chamber into Dragon's Back Chamber with grass cables. Because, then it was no 'rebirth without soul', but an accident of a loved one. Hence, Homo naledi would descend into Dinaledi chamber. Also in case of monkeys, no fallen babies would be left in Dinaledi Chamber:
https://www.youtube.com/watch?v=xg79mkbNaTg
The time span of the deposits.
The intentionality argument hinges on the implied improbability of over 15 independent rare events occurring in one spot. However, this is inversely proportional to time span. Thus the 99ka range (335-236ka) also argues against the burial hypothesis. Even with a restricted span of 20-50ka and an optimistic ~100 individuals, that’s still 200-500 years interval per burial. In my opinion this is simply too low to speak of a cultural trait. How could such a cultural trait be passed on with intermittent appearances every 30 generations, or even a fraction of that? A modest population with a death rate of 1 or 2 per year would produce thousands of corpses in the time involved. Since most deaths occur in the core area, the random probability of one or two dying in any given spot becomes quite high. In fact, the problem for any ‘natural’ explanation may well be how to explain the paucity of remains in the rest of the cave system! Presumably the upper sectors of the caves were exposed to the more usual effects of carnivore + scavenger deterioration. For the disposal hypothesis, on the other hand, a burial rate of ca. 1 in 1000 group members, one burial in 20 to 30 generations at best, again seems much too low to speak of a ‘cultural’ phenomenon.'
Michael I Christie:
Q.3: How so many? These events need only happen once per millennium to produce the 15 to ~100 individuals estimated to lie in the chamber in only 100ka, even without an occasional mother-infant or pair of any sort. This is well within the estimated range of the deposits.
Our comment:
An interesting postulation is the following: There are too few burials for the 100 ka that Homo naledi resided in the cave. But does not 335-236 years indicate the concatenation of the time intervals from the different dating methods? It is the estimated widest time interval in which Homo naledi must have been in the cave. I think in reality it must be confined to some generations.
And are there any signs of the usual carnivore + scavenger deterioration in the cave?
Michael I Christie:
H3. Predator accumulation: ‘no evidence’ in the Dinaledi Chamber seems consistent with the evidence. The ~1550 bones represents a large sample, enough to yield at least some evidence. That none was found definitely needs an explanation, more so because the adjacent chamber apparently has plenty of such predatory deposits.
Michael I Christie:
On the basis of direct dating of three of the 15 individuals recovered and stratigraphic constraints Dirks et al. [2] conclude that the Dinaledi Chamber hominin material was deposited between 236ka and 335ka, though there is some indication that part of the material could be even younger.
Elsewhere we concluded that Homo naledi could have been disappointed in rebirth without soul and for that reason stopped with these cumbersome burials.
If Homo naledi really would have been there for 100,000 years, we would see a lot of evidence thereof. Would they have had enough tribal and military stability to stay so long in the same region and protect their cave? Unbelievable, for then they must have been super intelligent creatures, certainly capable of making grass cords...
Michael I Christie:
Q.3: How so many? These events need only happen once per millennium to produce the 15 to ~100 individuals estimated to lie in the chamber in only 100ka, even without an occasional mother-infant or pair of any sort. This is well within the estimated range of the deposits.
Our comment:
An interesting postulation is the following: There are too few burials for the 100 ka that Homo naledi resided in the cave. But does not 335-236 years indicate the concatenation of the time intervals from the different dating methods? It is the estimated widest time interval in which Homo naledi must have been in the cave. I think in reality it must be confined to some generations.
And are there any signs of the usual carnivore + scavenger deterioration in the cave?
Michael I Christie:
H3. Predator accumulation: ‘no evidence’ in the Dinaledi Chamber seems consistent with the evidence. The ~1550 bones represents a large sample, enough to yield at least some evidence. That none was found definitely needs an explanation, more so because the adjacent chamber apparently has plenty of such predatory deposits.
Michael I Christie:
On the basis of direct dating of three of the 15 individuals recovered and stratigraphic constraints Dirks et al. [2] conclude that the Dinaledi Chamber hominin material was deposited between 236ka and 335ka, though there is some indication that part of the material could be even younger.
Elsewhere we concluded that Homo naledi could have been disappointed in rebirth without soul and for that reason stopped with these cumbersome burials.
If Homo naledi really would have been there for 100,000 years, we would see a lot of evidence thereof. Would they have had enough tribal and military stability to stay so long in the same region and protect their cave? Unbelievable, for then they must have been super intelligent creatures, certainly capable of making grass cords...
Conclusions:
- Survival strategies from baboons cannot directly be compared with Homo naledi. That is the major flaw in this article.
- Sometimes the Rising Star Cave might have served as a refuge, but then apparently without leaving any marks of use in Dragon's Back Chamber. A systematic use of the cave is not realistic but is also not assumed by Christie.
- The occupation hypothesis - but then without victims falling into the Chute, since we need Dinaledi Chamber for burials - can exist alongside the cemetery hypothesis, but that would be profane and would not have been acceptable for Homo naledi. So, we must choose between the burial or the occupation hypothesis.
- The cave is indefensible against Homo erectus who would block Superman's Crawl from the outside. In theory Homo naledi could have used the Dragon's Back Chamber incidentally as a refuge against predators and then have barricaded Superman's Crawl from the Dragon's Back inside. But then we would expect a lot of stones in the Dragon's Back for defense against predators. Then there must also be found scratches on the walls of the Crawl. And indeed, incidentally, they could have forgotten to shut the door. Then the predator hypotheses from Christie are realistic. Then a fall into the Chute is theoretically possible.
- We maintain the 'no occupation assumption' because living in the cave is very impractical and disputable as defense. It also conflicts with the cave as a sanctuary, but that is an illegitimate argument in falsifying occupation. And we have also rejected fire or torches as they are unnecessary and complementary tools to grass cables.
- 3D-mapping is not a necessary assumption to our Dinaledi scenario any longer, because Homo naledi was able to make grass ropes. So Homo naledi did not need this quality of baboons, though we still assume they were able to.
- Sometimes the Rising Star Cave might have served as a refuge, but then apparently without leaving any marks of use in Dragon's Back Chamber. A systematic use of the cave is not realistic but is also not assumed by Christie.
- The occupation hypothesis - but then without victims falling into the Chute, since we need Dinaledi Chamber for burials - can exist alongside the cemetery hypothesis, but that would be profane and would not have been acceptable for Homo naledi. So, we must choose between the burial or the occupation hypothesis.
- The cave is indefensible against Homo erectus who would block Superman's Crawl from the outside. In theory Homo naledi could have used the Dragon's Back Chamber incidentally as a refuge against predators and then have barricaded Superman's Crawl from the Dragon's Back inside. But then we would expect a lot of stones in the Dragon's Back for defense against predators. Then there must also be found scratches on the walls of the Crawl. And indeed, incidentally, they could have forgotten to shut the door. Then the predator hypotheses from Christie are realistic. Then a fall into the Chute is theoretically possible.
- We maintain the 'no occupation assumption' because living in the cave is very impractical and disputable as defense. It also conflicts with the cave as a sanctuary, but that is an illegitimate argument in falsifying occupation. And we have also rejected fire or torches as they are unnecessary and complementary tools to grass cables.
- 3D-mapping is not a necessary assumption to our Dinaledi scenario any longer, because Homo naledi was able to make grass ropes. So Homo naledi did not need this quality of baboons, though we still assume they were able to.
- Here we see Ockham's razor misused, because Homo naledi needed no 3D-mapping at all, for he invented ropes and sticks and spears already 7 million years earlier. The grass-cable assumption is a sufficient condition for routing through The Rising Star Cave.
- The problem with above article is that the 'most parsimonious' solution places Homo naledi alongside monkeys, while they actually belong more to humans. Then the state of nature from Homo naledi is denied. This is the wrong use of the principle of parsimony and an unreasonable flight into 'natural' causes.
- So, because we assume grass cables as sufficient condition to reach Dinaledi Chamber, we can skip 3D-mapping, echolocation and fire.
- We do not expect elderly people and toddlers climbing haphazardly on Dragon's Back and falling into Dinaledi Chamber. The age structure of the bodily remains shows a cemetery. And in case of danger they simply would block the Chute. Because, if they did not believe in a cemetery, why would they let this hole open? Maybe because they could not drag big stones through Superman's Crawl.
ADDENDUM
Michael I Christie:
The flood-induced Trap Scenario
Given the possibility that hominins could use the middle cave as a ‘water hole’ or dormitory, Dragon’s Back Chamber can become a passive trap if the water level in the cave increased by a mini flood or rose overnight, as might be expected in a seasonally wet-dry environment. Every year at the end of the dry season they would have to go deep into Dragon’s Back to find water. Because Superman’s Crawl is at ‘floor’ level and very low, even a modest flood from the first rains would seal the outlet forcing them up Dragon’s Back or any other ledge in the chamber. Once trapped in this chamber the probability of one or several hominins finding their way to the top of Dragon’s Back and into the chute is reasonably high, especially if the raised water level persisted a few days.
https://elifesciences.org/articles/24232
New fossil remains of Homo naledi from the Lesedi Chamber, South Africa (John Hawks, Marina Elliott et al.)
https://elifesciences.org/articles/24232
New fossil remains of Homo naledi from the Lesedi Chamber, South Africa (John Hawks, Marina Elliott et al.)
After the discovery was reported, a number of questions still remained. These questions included: why were so many fossils from a single species found at the one site, and how did they come to rest so far into the cave system? Possible explanations such as H. naledi living in the cave or being washed in by a flood were considered but ruled out. Instead, the evidence was largely consistent with intact bodies being deliberately disposed of in the cave and then decomposing.
Michael I Christie:
A question of improbabilities
The physical difficulty of hauling corpses in is so obvious it is one of the most cited objections. Again, lack of trauma in such a large sample strongly argues against the notion that the individuals died prior to reaching the chamber. It is inconceivable
that over countless cases nobody ever dropped a body as they were struggling in the dark with a heavy load up Dragon’s Back, about 11 meters or 7 erect “naledi” high (Figure 2). To illustrate, if the probability of hauling one body in without a scratch is say 85%, then the probability of succeeding with over a dozen is less than 12%. That assumes of course that none of the bodies had suffered perimortem bone-trauma, highly unlikely in the harsh african environment [11]. If 75% of deaths are bone-trauma free the likelihood of hauling 13 intact skeletons into the chamber in a row drops below 1%. If p is lower than 50%, the end odds shrink to less than 1/10,000.
The key point is that the likelihood of getting a large number of trauma-free corpses is exponential (pn), so increasing the number of corpses means exponentially decreasing the probability. This is also true for rare events such as accidents, say ‘one per year’. In that case ten accidents in one year are very unlikely. But the probability of ‘at least ten’ random accidents occurring over increasing number of units of time is additive so, given enough time, they become a virtual certainty. Or, if you prefer, the probability of getting zero accidents (qn) becomes vanishingly small.
The lack of bone-trauma has been stressed as being so low that the most reasonable explanation is that these individuals died inside the Dinaledi Chamber in a way that was non-traumatic to bones. So the problem is more a question of how and why they
got there alive and uninjured. A natural explanation demands a very species-specific trap as described above or some other passive mechanism.
Our comment:
Michael, many thanks for this most interesting explanation. It is all possible, really, but 100 ka is a long period and we only need some contiguous generations, and there may have been a dry period and BTW, corpses might have been damaged by transport but not the bones broken. And they weighted only 40 kg, that's not too much. It is not all statistics in life. We must add the interaction of the attributed intellect from Homo naledi to the scenarios. And by religion, humans and probably also Homo naledi, have done the most weird things you can imagine.
This work is licenced under a Creative Commons Attibution-Non Commercial-ShareAlike 4.0 International Licence.
No comments:
Post a Comment