Thank you for your very kind and thoughtful reply. I’d like to respond to a few points you raised.
So I am confused…why would you look for a sharp moment when human rationality arises? I’m a bit unsure [about] your reasoning…
First of all, I should state that my opinions on human origins have evolved over time, and that a position which I may have argued for a few years ago may no longer represent my views today. The following article, which you cite, was written in 2012:
Adam, Eve and Monogenism: A Reply to Professor Kemp
As readers can see, it’s rather scrappy and incomplete in places. But even in that article, I wrote:
However, Professor Kemp and I would both maintain that our hominid ancestors did become rational literally overnight, when the first human soul was infused into a human body.
In my 2012 article, I defended the view that Homo ergaster/erectus was the first true human being with a rational soul, made in the image and likeness of God. (Coming from a Catholic background, I should explain for the benefit of my readers that Catholic theologians overwhelmingly tend to equate the image of God with rationality, as Aquinas did. The reason is that on the Aristotelian-Thomistic view, rationality is an open-ended capacity for grasping universal concepts, including the concepts of God and of right and wrong. Rationality, on this view, is not something that comes in halves: either you have it in full or you’re a brute beast, capable of only grasping particulars. Thus rationality literally has to appear overnight, in human prehistory. In order to convincingly discredit this view, an alternative model of rationality would need to be put forward, and it would also need to rebut the formidable philosophical arguments for the immateriality of rationality of rational thought. That’s not going to be an easy task, let me tell you.)
Anyway, back in 2012, I believed that there was enough evidence to conclude that Homo ergaster/erectus was capable of taking a carefully controlled sequence of steps in order to achieve a long-range goal (as shown by the Acheulean hand-axes he made), using fire to cook meat, fishing, creating aesthetic objects and caring for sick individuals over long periods of time. These facts suggested to me that he was a rational agent - a view which Ann Gauger continues to uphold. However, facts that have come to light since then have forced me to reconsider my views. For instance, the view that Acheulean hand-axes are cultural artifacts has been questioned: in 2016, Corbey et al., in a provocative article, argued that the production of these handaxes was probably not acquired by social learning, but was at least partly under genetic control. Handaxes, they contended, were “more like a bird’s song than a beatles’ tune.” Other scientists strongly disagree with this analysis, mounting a strong case that these artifacts are cultural, after all. For my part, I think the critical question is whether language would have been required in order to teach individuals how to make these tools, and on that particular point, the evidence is still doubtful.
Regarding cooking and fishing, it seems that the oldest good evidence of fire use goes back only 1 million years (not 1.9 million years, which is when Homo ergaster/erectus arose), and even then, it’s unclear whether the hominins who used fire (in the Wonderwerk cave in South Africa) knew how to start a fire from scratch. It seems that the earliest firm evidence for the controlled use of fire goes back only 400,000 years. The evidence that fishing may go back 750,000 years turned out to be fairly tendentious, too, and in actual fact, the earliest firm evidence for fishing dates back no more than 164,000 years. So I now think my original case for a cognitive “great leap forward” occurring at the advent of Homo ergaster/erectus was greatly overstated.
In 2013, I wrote a much more carefully-argued article for Uncommon Descent, titled:
Who was Adam and when did he live? Twelve theses and a caveat
In this article, I defended the view that the origin of human beings occurred around 1 million years ago, with the advent of Homo heidelbergensis. I found this view very attractive, as Heidelberg man was supposed to be the common ancestor of Homo sapiens, Neandertals and Denisovans. Since then, however, the validity of the taxon Homo heidelbergensis has been questioned, forcing another rethink on my part. I also noted in that article that according to Dubreuil (2010), the globularization of Homo sapiens’ cranium, which occurred gradually, between 300,000 and 100,000 years ago, was what enabled human beings’ production of art, symbolism, theory of mind, complex categorization and semantic processing. This was a significant concession, as Dubreuil himself had argued that Heidelberg man, who preceded Homo sapiens, was nonetheless capable of capable of long-term planning and moral decision-making (including self-sacrifice for the benefit of the group) - traits that we tend to associate with true human beings.
Since then, more evidence has come to light, causing me to question my earlier belief that Neandertal man was capable of using language (see here for instance), and I am now inclined to think that only the later specimens of Neandertal man, who interbred with our species, may have been truly human. Still, I may be wrong. Additionally, there is now good evidence of a cognitive breakthrough occurring in Africa between 320,000 and 500,000 years ago, which roughly coincides with the emergence of Homo sapiens. I might add that the earliest evidence for spears dates from no more than 500,000 years ago, and even that date is contested: the earliest firm evidence goes back 400,000 years. Prior to that time, humans didn’t use tools for hunting: they caught game animals by running them to death, which we were able to do thanks to our ability to sweat while running, and thereby lose body heat. What, no tools for game hunting? That doesn’t sound very clever to me.
So the upshot of all this is that it’s difficult to argue for the existence of beings with a mental life like our own, prior to 500,000 years ago. Perhaps the best piece of evidence to the contrary are the handaxes found at Kathu Pan, which do look elegant, I must admit. These go back to between 700,000 and 1 million years ago.
Notwithstanding the evidence for a cognitive breakthrough around 320,000 years ago, at the dawn of Homo sapiens, it remains uncertain whether such a breakthrough would have required the use of language, and whether human beings living then would have been capable of symbolism, art and religion, and for that matter, a theory of mind. All we can say at present is that these humans had mental maps of their surroundings over a radius of 30 miles in five different directions, and that they may have used ochre as well. If we look at modern human behavior as an ensemble, it seems to have arisen around 100,000 years ago.
So the way I read the evidence, it seems we became truly human between 500,000 and 100,000 years ago.
Joshua, you wrote:
The problem with looking for markers of cognitive breakthroughs is that they are really all over the place, with low resolution. Some people see a bigger jump at about 50 kya, and I see the biggest leap at 10 kya.
I’m curious. What archaeological evidence do you have for a cognitive breakthrough 10,000 years ago? I’d like to hear more about this. Perhaps I’ve been looking at the wrong data. For instance, how far back do you think religion goes?
You also write:
Not posted on Peaceful Science, but posted with Buggs, yes. Introgression data seems to push back the date from 400 kya to about 700 kya, or even 1 mya (but that is less certain). It seems that both Denisovans and Neanderthals interbred with Sapiens, and perhaps even other hominids. Not, however, that the “error bars” on these dates are very large. Perhaps plus or minus 100 to 200 kya. So it is possible you could squeak by at 500 kya, but 400 starts to stretch the limits too far. I would, if I were you, try to find a scenario less critically dependant on dates.
I accept the findings you cite, which would imply that the breakthrough that made us human post-dates the split between Homo sapiens and Neandertal man and Denisovan man. However, I understand that a scenario in which a single human pair, living 410,000 years ago, gave rise to all humans living today (barring limited interbreeding with Neandertals, which took place at a later date) is still scientifically possible. Is that right?
In my view, it is better to look at the Genesis narrative on its own terms, and posit that the the Image of God gradually develops (certainly with God’s providential work, and perhaps direct action) over thousands of years.
You could certainly make a strong case for gradual development on the basis of the archaeological evidence, but it faces some formidable theoretical difficulties, especially from a Judeo-Christian standpoint. For instance, take the God-given rights listed in the Declaration of Independence: the right to life, liberty and the pursuit of happiness. It seems to me that either a creature has these rights or it doesn’t. Ditto immortality (although one could argue that there are degrees of happiness in Heaven). So the first question I’d want to answer is: when did our ancestors acquire an immortal soul, and when did they acquire a right to life?
Before I sign off, I’d like to thank you once again, Joshua, for clarifying the meaning of the Fall, on the model you are defending. I have to say I find it far less theologically objectionable than I had expected it to be, and I shall think it over carefully. And now, over to you.