Since the start of this blog I have been writing about human evolution from the physical point of view. I dearly love to think and talk about the different hominin species starting from the point in time of the last common ancestor we had with chimpanzees, a time of about 7-8 million years ago. The whole deal with evolution and speciation and morphology changes and tool making and beginnings of complex cultures is just about as fascinating a topic as there could ever be.
As much as I am in love with Paleoanthropology from the actual physical evidence perspective, (who doesn’t love a good fossil skull?) human consciousness is another topic I have thought about for decades and fascinates me even more.
We live in a thought world and not the physical world. I know, sounds like some new age or eastern metaphysical kinda stuff doesn’t it. There is no other conclusion I can come to. Going forward this year I hope to share how and why I came to that belief.
I am not saying we don’t exist in the physical world. I am not saying it’s all an illusion or any of that stuff. The world is full of half-truths courtesy of our consciousness’s ability to envision deep and elaborate constructs. I am saying that as a practical matter we live in a world of thought and everything around us that we interact with is a manifestation of thought. From the time you wake in the morning till the time you go to sleep at night everything you interact with is a manifestation of thought.
All the interactions you have that are external to yourself and all the thoughts you have that are internal take place in your consciousness. Reading this right now is an example. To be cognizant of your own consciousness is to be human.
Along the timeline of human evolution, the physical changes of the various species of hominins are pretty well documented. Doesn’t mean that every single step along the way has been documented with fossil evidence, there are still transitional gaps to be filled but surely, we have the big picture.
When and how did our consciousness evolve to the point it is today? This question is a hard one because consciousness leaves no physical evidence itself. One way to study consciousness is to look at behavior. How can we know and analyze the behaviors of hominins 500,000 years ago? This is especially difficult because archeological evidence for the level of consciousness would be mostly ephemeral in nature. It is very hard for anything not associated with a stone industry (stone tools) to last for hundreds of thousands of years.
The seat of consciousness is in the mind and the physical location of the mind is in the brain.
The Australopiths typically had a brain size of less than 500 cubic centimeters or roughly a third the size of modern man. Homo erectus’ brain size was about 1050 cubic centimeters with a brain structure similar to modern man. In fact, Homo erectus was very similar morphologically to modern man in every respect. Homo heidelbergensis brain size averaged 1200 cubic centimeters, which is only slightly smaller than modern man’s. They too basically had the same body as modern man. We don’t have any Denisovan skulls but Homo neanderthalensis had a brain that averaged the same as modern man’s. Neanderthal’s and Homo sapiens average between 1,300 and 1,500 cubic centimeters. For a long time, it was thought that Neanderthals enjoyed on average a larger brain size than modern man but in recent years the thinking on that has changed and now there is a general consensus they both shared similar brain sizes.
There was a substantial increase in brain size from the Australopiths to Homo erectus, in fact over a doubling in size. But from Homo erectus to Heidelberg man not that much of an increase and from then on brain size falls within the range of modern man. While the average of modern man’s brain size is 1,300 to 1,500 cubic centimeters there is a sizable percentage of world’s population that has a brain size in the 1,100 to 1,200 cubic centimeter range. The point of all this brain size business is from Homo heidelbergensis on, brain size has been within a range of what we have today. Also, we basically have the same body with all the same body parts. Even down to the very important hyoid bone, a bone that facilitates speech.
This little fragile bone is found in heidelbergensis and it is the same as found in modern man. Homo erectus also has a hyoid bone but it is less developed and therefore it makes erectus less capable of complex speech. Interestingly Homo heidelbergensis also has an ear canal the same as modern man’s lending more credence to his speech capabilities as it allows him to discern subtle inflections of sound.
Since the partial mapping of DNA for Neanderthals has been accomplished it has been established that certain genetic traits related to speech and language in modern man are present in Neanderthals and Denisovans alike. There has not been a good DNA sample for Homo heidelbergensis so we are not sure yet but it seems likely given the other similarities.
How does this relate to consciousness? Good question. Without any scientific studies to back this up, it seems to me that starting with Homo heidelbergensis and its ability to express thoughts in a complex language that the evolution of consciousness began to take huge steps forward in terms of developing social interactions and cultural constructs.
What we call modern behaviors or behavioral modernity now seems to have started 500,000 years ago or even earlier. Shocking statement I know, especially given the term Cognitive Revolution. Cognitive Revolution refers to a theory that 70,000 to 50,000 years ago Homo sapiens experienced a gene mutation which expanded their consciousness and resulted in the behavioral modernity that we experience today. This theory once widely embraced is now is under heavy scrutiny.
The level of consciousness for individuals is certainly displayed by behavior. Pre-historical behavior is derived from archeological evidence. Archaeologists and Paleoanthropologists are really, really good at deducing and theorizing about behaviors from the recovered artifacts of man. But that relies on the recovered artifacts. The farther back in time we go the less artifacts there are. The stone industries or stone tools being the exception for the obvious reason.
Other artifacts of man that were made of bone or wood or animal skin or any organic material is likely not to last very long. Organic material decomposes fairly rapidly in most cases. Other clues such as ritual, tribal organization, use of domestic spaces, trade, methods of harvesting resources, art, music, body adornment are even more likely to be lost to time in short order.
Therefore, a lot of what we think about the culture and social structure of ancient man relies on speculation from the scant evidence that has survived. Fortunately, there are clues that have been left behind.
The most telling clue to the level of consciousness and behavioral modernity is applying meaningful significance to experiences through symbolic behavior, a subject near and dear to my heart.
It may well be the defining characteristic of a fully modern consciousness to make arbitrary symbols with the intent of representing abstract concepts, people and objects then to use these symbols, which can be visual or vocal, in various cultural practices like ritual, communications and art as a part of everyday life.
How far back can we trace these symbolic behaviors? Indeed, how far back can we? I am going to approach the subject of symbolic behavior from a few different angles including the heavy science of the brain to what some would call the ethereal science of consciousness. I plan to throw in a little quantum mechanics and non-local consciousness talk too just for the heck of it. I hope you will like what I will have to say.