## Posts Tagged ‘arithmetic’

### Mathematics started in prehistory with counting and the study of shapes

January 8, 2021

Mathematics today is classified into more than 40 different areas by journals for publication. I probably heard about the 3 R’s (Reading, Riting and Rithmetic) first at primary school level. At high school, which was 60 years ago, mathematics consisted of arithmetic, geometry, algebra, trigonometry, statistics and logic – in that order. I remember my first class where trigonometry was introduced as a “marriage of algebra and geometry”. Calculus was touched on as advanced algebra. Some numerical methods were taught as a part of statistics. If I take my own progression, it starts with arithmetic, moves on to geometry, algebra and trigonometry and only then to calculus and statistics, symbolic logic and computer science. It was a big deal when, at 10, I got my first “compass box” for geometry, and another big deal, at 13, with my first copy of trigonometric tables. At university in the 70s, Pure Mathematics was distinguished from Applied Engineering Mathematics and from Computing. In my worldview, Mathematics and Physics Departments were where the specialist, esoteric mysteries of such things as topology, number theory, quantum algebra, non-Euclidean geometry and combinatorics could be studied.

I don’t doubt that many animals can distinguish between more and less. It is sometimes claimed that some primates have the ability to count up to about 3. Perhaps they do, but except for in the studies reporting such abilities, they never actually do count. No animals apply counting, They don’t exhibit any explicit understanding of geometrical shapes or structures, though birds, bees, ants and gorillas seem to apply some structural principles, intuitively, when building their nests. Humans, as a species, are unique in not only imagining but also in applying mathematics. We couldn’t count when we left the trees. We had no tools then and we built no shelters. So how did it all begin?

Sometimes Arithmetic, Geometry and Algebra are considered the three core areas of mathematics. But I would contend that it must all start with counting and with shapes – which later developed into Arithmetic and Geometry. Algebra and its abstractions came much later. Counting and the study of shapes must lie at the heart of how prehistoric humans first came to mathematics. But I would also contend that counting and observing the relationship between shapes would have started separately and independently. They both require a certain level of cognition but they differ in that the study of shapes is based on observations of physical surroundings while counting requires invention of concepts in the abstract plane. They may have been contemporaneous but they must, I think, have originated separately.

No circle of standing stones would have been possible without some arithmetic (rather than merely counting) and some geometry. No pyramid, however simple, was ever built without both. No weight was dragged or rolled up an inclined plane without some understanding of both shapes and numbers. No water channel that was ever dug did not involve some arithmetic and some geometry. Already by the time of Sumer and Babylon, and certainly by the time of the Egyptians and the Harappans, the practical application of arithmetic and geometry and even trigonometry in trade, surveying, town planning, time-keeping and building were well established. The sophisticated management of water that we can now glimpse in the ancient civilizations needed both arithmetic and geometry. There is not much recorded history that is available before the Greeks. Arithmetic and Geometry were well established by the time we come to the Greeks who even conducted a vigorous discourse about the nobility (or divinity) of the one versus the other. Pythagoras is not happy with arithmetic since numbers cannot give him – exactly – the hypotenuse of a right triangle of sides of equal length (√2). Which he can so easily draw. Numbers could not exactly reflect all that he could achieve with a straight edge and a compass. The circle could not be squared. The circumference was irrational. The irrationality of the numbers needed to reflect geometrical shapes was, for the purists, vulgar and an abomination. But the application of geometry and arithmetic were common long, long before the Greeks. There is a great distance before counting becomes arithmetic and the study of shapes becomes geometry but the roots of mathematics lie there. That takes us back to well before the Neolithic (c. 12,000 years ago).

That geometry derives from the study of shapes and the patterns and relationships between shapes, given some threshold level of cognition, seems both obvious and inevitable. Shapes are real and ubiquitous. They can be seen in all aspects of the natural world and can be mimicked and constructed. The arc of the sun curving across the sky creates a shape. Shadows create shapes. Light creates straight lines as the elevation of the sun creates angles. Shapes can be observed. And constructed. A taut string to give a straight line and the calm surface of a pond to give a level plane. A string and a weight to give the vertical. A liquid level to give the horizontal. Sticks and shadows. A human turning around to observe the surroundings created a circle. Strings and compasses. Cave paintings from c. 30,000 years ago contain regular shapes. Circles and triangles and squares. Humans started not only observing, but also applying, the relationships between shapes a very long time ago.

Numbers are more mystical. They don’t exist in the physical world. But counting the days from new moon to new moon for a lunar month, or the days in a year, were also known at least 30,000 years ago. Ancient tally sticks to count to 29 testify to that. It would seem that the origins of arithmetic (and numbers) lie in our ancient prehistory and probably more than 50,000 years ago. Counting, the use of specific sounds as the representation of abstract numbers, and number systems are made possible only by first having a concept of identity which allows the definition of one. Dealing with identity and the nature of existence take us before and beyond the realms of philosophy or even theology and are in the metaphysical world. The metaphysics of existence remain mystical and mysterious and beyond human cognition, as much today as in prehistoric times. Nevertheless, it is the cognitive capability of having the concept of a unique identity which enables the concept of one. That one day is distinguishable from the next. That one person, one fruit, one animal or one thing is uniquely different to another. That unique things, similar or dissimilar, can be grouped to create a new identity. That one grouping (us) is distinguishable from another group (them). Numbers are not physically observable. They are all abstract concepts. Linguistically they are sometimes bad nouns and sometimes bad adjectives. The concept of one does not, by itself, lead automatically to a number system. That needs in addition a logic system and invention (a creation of something new which presupposes a certain cognitive capacity). It is by definition, and not by logic or reason or inevitability, that two is defined as one more than the identity represented by one, and three is defined as one more than two, and so on. Note that without the concept of identity and the uniqueness of things setting a constraint, a three does not have to be separated from a two by the same separation as from two to one. The inherent logic is not itself invented but emerges from the concept of identity and uniqueness. That 1 + 1 = 2 is a definition not a discovery. It assumes that addition is possible. It is also significant that nothingness is a much wider (and more mysterious and mystical) concept than the number zero. Zero derives, not from nothingness, but from the assumption of subtraction and then of being defined as one less than one. That in turn generalises to zero being any thing less than itself. Negative numbers emerge by extending that definition. The properties of zero are conferred by convention and by definition. Numbers and number systems are thus a matter of “invention by definition”, but constrained by the inherent logic which emerges from the concept of identity. The patterns and relationships between numbers have been the heady stuff of number theory and a matter of great wonder when they are discovered, but they are all consequent to the existence of the one, the invention of numerals and the subsequent definition that 1 + 1 = 2. Number theory exists only because the numbers are defined as they are. Whereas the concept of identity provides the basis for one and all integers, a further cognitive step is needed to imagine that the one is not indivisible and then to consider the infinite parts of one.

Mere counting is sometimes disparaged, but it is, of course, the most rudimentary form of a rigorous arithmetic with its commutative, associative and distributive laws.

The cognitive step of getting to count in the first place is a huge leap compared to the almost inevitable evolution of counting into numbers and then into an arithmetic with rigorous laws. We will never know when our ancestors began to count but it seems to me – in comparison with primates of today – that it must have come after a cognitive threshold had been achieved. Quite possibly with the control of fire and after the brain size of the species had undergone a step change. That takes us back to the time of homo erectus and perhaps around a million years ago.

Nearly all animals have shape recognition to some extent. Some primates can even recognise patterns in similar shapes. It is plausible that recognition of patterns and relationships between shapes only took off when our human ancestors began construction either of tools or of rudimentary dwellings. The earliest tools (after the use of clubs) were probably cutting edges and these are first seen around 1.8 million years ago. The simplest constructed shelters would have been lean-to structures of some kind. Construction of both tools and shelters lend themselves naturally to the observation of many geometrical shapes; rectangles, polygons, cones, triangles, similar triangles and the rules of proportion between similar shapes. Arches may also have first emerged with the earliest shelters. More sophisticated tools and very simple dwellings take us back to around 400,000 years ago and certainly to a time before anatomically modern humans had appeared (c. 200,000 years ago). Both rudimentary counting and a sense of shapes would have been present by then. It would have been much later that circles and properties of circles were observed and discovered. (Our earliest evidence of a wheel goes back some 8,000 years and is the application of a much older mathematics). Possibly the interest in the circle came after a greater interest in time keeping had emerged. Perhaps from the first “astronomical” observations of sunrise and sunset and the motion of the moon and the seasons. Certainly our ancestors were well-versed with circles and spheres and their intersections and relationships by the time they became potters (earlier than c. 30,000 years ago).

I suspect it was the blossoming of trade – rather than the growth of astronomy – which probably helped take counting to number systems and arithmetic. The combination of counting and shapes starts, I think, with the invention of tools and the construction of dwellings. By the time we come to the Neolithic and settlements and agriculture and fortified settlements, arithmetic and geometry and applied mathematics is an established reality. Counting could have started around a million years ago. The study of shapes may have started even earlier. But if we take the origin of “mathematics” to be when counting ability was first combined with a sense of shapes, then we certainly have to step back to at least 50,000 years ago.

### Number theory was probably more dependent upon live goats than on raindrops

June 14, 2017

It used to be called arithmetic but it sounds so much more modern and scientific when it is called number theory. It is the branch of mathematics which deals with the integers and the relationships between them. Its origins (whether one wants to call it a discovery or an invention) lie with the invention of counting itself. It is from where all the various branches of mathematics derive. The origin of counting can be said to be with the naming of the integers, and is intimately tied to the development of language and of writing and perhaps goes back some 50,000 years (since the oldest known tally sticks date from some 30,000 years ago).

How and why did the naming of the integers come about?  Why were they found necessary (necessity being the cause of the invention)? Integers are whole numbers, indivisible, complete in themselves. Integers don’t recognise a continuum between themselves. There are no partials allowed here. They are separate and discrete and number theory could as well be called quantum counting.

Quite possibly the need came from counting their livestock or their prey. If arithmetic took off in the fertile crescent it well may have been the need for trading their live goats among themselves (integral goats for integral numbers of wives or beads or whatever else they traded) which generated the need for counting integers. Counting would have come about to fit their empirical observations. Live goats rather than carcasses, I think, because a carcass can be cut into bits and is not quite so dependent upon integers.  Quanta of live goat, however, would not permit fractions. It might have been that they needed integers to count living people (number of children, number of wives …..) where fractions of a person were not politically correct.

The rules of arithmetic – the logic – could only be discovered after the integers had been named and counting could go forth. The commutative, associative and distributive properties of integers inevitably followed. And the rest is history.

But I wonder how mathematics would have developed if the need had been to count raindrops.

After all:

2 goats + 2 goats = 4 goats, and it then follows that

2 short people + 2 short people = 4 short people.

But if instead counting had been inspired by counting raindrops, they would have observed that

2 little raindrops + 2 little raindrops = 1 big raindrop.

They might then have concluded that

2 short people + 2 short people = one tall person

and history would then have been very different.