Tuesday, January 21, 2020

Symbolic Thinking: The Mindset of Culture

 In Prehistoric Art and Civilization (1998), Denis Vialou summarizes the history of mankind:

More than two million years ago, Homo habilis invented the tool.  Next, Homo erectus made use of fire; then Homo sapiens conquered the world.  In just a few millennia, in the era we call the Palaeolithic, human beings, walking upright and with tools in each hand, imposed a new knowledge and a new way of life on the world.

Human inventiveness began with the discovery of tools 1.76 million years ago from the first knapped hand ax, fire 400 millennia ago, the invention of language at least 200,000 years ago, artistic expression, and written language only 5,000 years ago.  From these long-ago origins came computing and artificial intelligence, the moon landing, and exploration of other solar systems and a Mars mission in the wings.  In fact, all technology includes the very first inventions from the ancient world and prehistory, including the stringent mental exercise of mathematics, and were basic to all the applied science of the 20th and 21st centuries and their advances in bioscience, genetics, computing, the global space program, and others based on Big Data.  Symbols are a type of tool that keeps on developing the mindset as ideas multiply and find expression in problem solving.

Indispensable to all these stunning achievements is the longest-running of them all: the aggregate development of culture by thousands of human generations whose lifetimes worked nonstop to improve and adapt the myriad ways in which we can think, behave, and make decisions, both as collective minds in groups and as solo individuals working out the problems of the universe as well as our next cup of coffee.  The strength and plasticity of culture, as well as the human brain, makes us the world’s most adaptable and successful species—through the collective brain and creativity of humankind. 

Symbolic thinking

Our unique human ability to imagine, manufacture, and put to use symbols is an act of absolute liberation from the material world and from the present moment, allowing us to see beyond what is in front of us, backwards into the past, and forward into the rich potential of the future.  Emerging evidence from archeology is showcasing that symbolism began to emerge as part of a great cognitive revolution in the form of art (now beyond 40,000 years ago) and mathematics at 30,000.  While the flowering of mathematics in applied problem solving goes back only 500 years to the Scientific Revolution, its origins are ancient and worldwide as a symbolic language of its own that developed independently as a trained skill, from simple computation to defining infinity. 

However great the potential of abstract thinking, engineering still must fit the numbers and concepts to the human form.  The operations researcher must fit the design of space vehicles like the LEM to the dimensions of the human body and brain.  Animal traps and weapons ballistics had to fit what humans could fashion, carry, and track.   In this way, our own inventions must work for us.  Culture, as the Ur-invention, became the invisible force driving our brains, bodies, and behavior both as individuals and groups (thinking, learning, expression, and problem solving), from our first survival on the African plains to the sophistication of urban life on-earth and off.  On the Internet and in subcultures, using technological acumen and prolixity---cultural intelligence underlies and animates everything human, yet is certainly the least understood of anything humans have produced. 


Culture could not begin its own invention without our species' ability to think symbolically.  This mindset began in the Paleolithic, the early phase of the Stone Age, about 2.5 million years in duration, marked by stone, wood, and bone tools, and cave art starting with the monumental act of leaving handprints created by our prehistoric relatives.  These handprints in red ochre have moved back in time from the Maltravieso cave in Spain, dated back 64,000 years and painted by a Neanderthal, well before Altimiria’s bison of 16,000 to 9,000 BCE, the “Sistine Chapel of Paleolithic Art.”  Discoveries in the Blombos cave in South Africa then moved the clock back on art-making with a 100,000-year-old pre-European animal-bone paintbrush and palettes, abalone shells for mixing red ochre paint, and sea-snail shells with holes for stringing and wearing as jewelry. 

In his article on symbolic thought (New York Times, Dec. 5, 2014), Ferris Jabr notes the significance of a simple handprint:  “The suggestion of a human hand on a cave wall, a nation’s flag, even a Rothko—each is a powerful mental heuristic designed to conjure a particular emotion, a memory, an idea.”  The elegance of symbols, Jabr says, is that they bypass the issues of changing the world in the act of changing the way we perceive it, enlarging its possibilities by acts of thought alone.  That is, by the power of ideas.


Evidence of language is also moving backwards on the timescale of human evolution.  Like art and jewelry, speech is intimately involved in conceptual and imaginative thinking.  Recent research points to language development as occurring millions of years ago rather than the benchmark of just 200,000 (Sawallis et al., 2019).  Two forces, first, the reshaping of the human throat, and second, syntax, the way words work together in sequential order to convey linguistic meaning, are considered the critical events in the body and brain that make symbolic communication possible. Unfortunately, linguistic evolution, unlike physical development, doesn’t have much data to work with because soft tissue doesn’t leave fossil evidence.  But speech is not just a physical and muscular act made possible by laryngeal descent—our lowered larynx compared to other primates.  It is a mental capacity that is at once intensely social and inherently symbolic. 


The oldest known mathematical artifact is the Wolf Bone of Czechoslovakia, with 55 notches in two groupings, dated at 30,000 years ago; the second-oldest is the Ishango bone discovered in Zaire, dated 10,000 years earlier, with three columns of marks suggesting computation either as a tally or a calendar.  Hunter-gatherer societies used number systems, and the names for numbers can be tracked as they gradually increased in independent lexicons over time. 

The earliest mathematical texts are Egyptian and Babylonian dating to 2,000 BCE, covering arithmetic, geometry, and the Pythagorean theorem, continuing in ancient Greece.  The Greeks introduced deductive reasoning and formal proofs to conceptual thinking about math.  The Romans applied math to surveying, structural and mechanical engineering, bookkeeping, lunar and solar calendars, and the arts.  The Chinese added place value and negative numbers.  The Hindu-Arabic numeral system is in worldwide use today, coming from India in the first thousand years BCE.  From the Maya of Mexico and Central America came the most critical concept to computation – the zero, a triumph of abstract cognition.