Category Archives: History of Logic

Mega inanity

Since the lead up to the Turing centennial in 2012 celebrating the birth of one of the great meta-mathematicians of the twentieth century, Alan Mathison Turing, I have observed with increasing horror the escalating hagiographic accounts of Turing’s undoubted historical achievements and the resulting perversion of the histories of twentieth-century science, mathematics and technology and in particular the history of computing.

This abhorrence on my part is not based on a mere nodding acquaintance with Turing’s name but on a deep and long-time engagement with the man and his work. I served my apprenticeship as a historian of science over many years in a research project on the history of formal or mathematical logic. Formal logic is one of the so-called formal sciences the others being mathematics and informatics (or computer science). I have spent my whole life studying the history of mathematics with a special interest in the history of computing both in its abstract form and in its technological realisation in all sorts of calculating aids and machines. I also devoted a substantial part of my formal study of philosophy to the study of the philosophy of mathematics and the logical, meta-logical and meta-mathematical problems that this discipline, some would say unfortunately, generates. The history of all of these intellectual streams flow together in the first half of the twentieth century in the work of such people as Leopold Löwenheim, Thoralf Skolem, Emil Post, Alfred Tarski, Kurt Gödel, Alonso Church and Alan Turing amongst others. These people created a new discipline known as meta-mathematics whilst carrying out a programme delineated by David Hilbert.

Attempts to provide a solid foundation for mathematics using set theory and logic had run into serious problems with paradoxes. Hilbert thought the solution lay in developing each mathematical discipline as a strict axiomatic systems and then proving that each axiomatic system possessed a set of required characteristics thus ensuring the solidity and reliability of a given system. This concept of proving theories for complete axiomatic systems is the meta- of meta-mathematics. The properties that Hilbert required for his axiomatic systems were consistency, which means the systems should be shown to be free of contradictions, completeness, meaning that all of the theorems that belong to a particular discipline are deductible from its axiom system, and finally decidability, meaning that for any well-formed statement within the system it should be possible to produced an algorithmic process to decide if the statement is true within the axiomatic system or not. An algorithm is like a cookery recipe if you follow the steps correctly you will produce the right result.

The meta-mathematicians listed above showed by very ingenious methods that none of Hilbert’s aims could be fulfilled bringing the dream of a secure foundation for mathematics crashing to the ground. Turing’s solution to the problem of decidability is an ingenious thought experiment, for which he is justifiably regarded as one of the meta-mathematical gods of the twentieth century. It was this work that led to him being employed as a code breaker at Bletchley Park during WW II and eventually to the fame and disaster of the rest of his too short life.

Unfortunately the attempts to restore Turing’s reputation since the centenary of his birth in 2012 has led to some terrible misrepresentations of his work and its consequences. I thought we had reach a low point in the ebb and flow of the centenary celebrations but the release of “The Imitation Game”, the Alan Turing biopic, has produced a new series of false and inaccurate statements in the reviews. I was pleasantly pleased to see several reviews, which attempt to correct some of the worst historical errors in the film. You can read a collection of reviews of the film in the most recent edition of the weekly histories of science, technology and medicine links list Whewell’s Gazette. Not having seen the film yet I can’t comment but I was stunned when I read the following paragraph from the abc NEWS review of the film written by Alyssa Newcomb. It’s so bad you can only file it under; you can’t make this shit up.

The “Turing Machine” was the first modern computer to logically process information, running on interchangeable software and essentially laying the groundwork for every computing device we have today — from laptops to smartphones.

Before I analyse this train wreck of a historical statement I would just like to emphasise that this is not the Little Piddlington School Gazette, whose enthusiastic but slightly slapdash twelve-year-old film critic got his facts a little mixed up, but a review that appeared on the website of a major American media company and as such totally unacceptable however you view it.

The first compound statement contains a double whammy of mega-inane falsehood and I had real problems deciding where to begin and finally plumped for the “first modern computer to logically process information, running on interchangeable software”. Alan Turing had nothing to do with the first such machine, the honour going to Konrad Zuse’s Z3, which Zuse completed in 1941. The first such machine in whose design and construction Alan Turing was involved was the ACE produced at the National Physical Laboratory, in London, in 1949. In the intervening years Atanasoff and Berry, Tommy Flowers, Howard Aikin, as well as Eckert and Mauchly had all designed and constructed computers of various types and abilities. To credit Turing with the sole responsibility for our digital computer age is not only historically inaccurate but also highly insulting to all the others who made substantial and important contributions to the evolution of the computer. Many, many more than I’ve named here.

We now turn to the second error contained in this wonderfully inane opening statement and return to the subject of meta-mathematics. The “Turing Machine” is not a computer at all its Alan Turing’s truly genial thought experiment solution to Hilbert’s decidability problem. Turing imagined a very simple machine that consists of a scanning-reading head and an infinite tape that runs under the scanning head. The head can read instructions on the tape and execute them, moving the tape right or left or doing nothing. The question then reduces to the question, which set of instructions on the tape come eventually to a stop (decidable) and which lead to an infinite loop (undecidable). Turing developed this idea to a machine capable of computing any computable function (a universal Turing Machine) and thus created a theoretical model for all computers. This is of course a long way from a practical, real mechanical realisation i.e. a computer but it does provide a theoretical measure with which to describe the capabilities of a mechanical computing device. A computer that is the equivalent of a Universal Turing Machine is called Turing complete. For example, Zuse’s Z3 was Turing complete whereas Colossus, the computer designed and constructed by Tommy Flowers for decoding work at Bletchley Park, was not.

Turing’s work played and continues to play an important role in the theory of computation but historically had very little effect on the development of real computers. Attributing the digital computer age to Turing and his work is not just historically wrong but is as I already stated above highly insulting to all of those who really did bring about that age. Turing is a fascinating, brilliant, and because of what happened to him because of the persecution of homosexuals, tragic figure in the histories of mathematics, logic and computing in the twentieth century but attributing achievements to him that he didn’t make does not honour his memory, which certainly should be honoured, but ridicules it.

I should in fairness to the author of the film review, that I took as motivation from this post, say that she seems to be channelling misinformation from the film distributors as I’ve read very similar stupid claims in other previews and reviews of the film.


Filed under History of Computing, History of Logic, History of Mathematics, Myths of Science

5 Brilliant Mathematicians – 4 Crappy Commentaries

I still tend to call myself a historian of mathematics although my historical interests have long since expanded to include a much wider field of science and technology, in fact I have recently been considering just calling myself a historian to avoid being pushed into a ghetto by those who don’t take the history of science seriously. Whatever, I have never lost my initial love for the history of mathematics and will automatically follow any link offering some of the same. So it was that I arrived on the Mother Nature Network and a blog post titled 5 brilliant mathematicians and their impact on the modern world. The author, Shea Gunther, had actually chosen 5 brilliant mathematicians with Isaac Newton, Carl Gauss, John von Neumann, Alan Turing and Benoit Mandelbrot and had even managed to avoid the temptation of calling them ‘the greatest’ or something similar. However a closer examination of his commentaries on his chosen subjects reveals some pretty dodgy not to say down right crappy claims, which I shall now correct in my usual restrained style.

He starts of fairly well on Newton with the following:

There aren’t many subjects that Newton didn’t have a huge impact in — he was one of the inventors of calculus, built the first reflecting telescope and helped establish the field of classical mechanics with his seminal work, “Philosophiæ Naturalis Principia Mathematica.” He was the first to decompose white light into its constituent colors and gave us, the three laws of motion, now known as Newton’s laws.

But then blows it completely with his closing paragraph:

We would live in a very different world had Sir Isaac Newton not been born. Other scientists would probably have worked out most of his ideas eventually, but there is no telling how long it would have taken and how far behind we might have fallen from our current technological trajectory.

This is the type of hagiographical claim that fans of great scientists tend to make who have no real idea of the context in which their hero worked. Let’s examine step by step each of the achievements of Newton listed here and see if the claim made in this final paragraph actually holds up.

Ignoring the problems inherent in the claim that Newton invented calculus, which I’ve discussed here, the author acknowledges that Newton was only co-inventor together with Leibniz and although Newton almost certainly developed his system first it was Leibniz who published first and it was his system that spread throughout Europe and eventually the world so no changes here if Isaac had not been born.

Newton did indeed construct the first functioning reflecting telescope but as I explained here it was by no means the first. It would also be fifty years before John Hadley succeeded in repeating Newton’s feat and finally making the commercial production of reflecting telescopes viable. However Hadley also succeeded in making working models of James Gregory’s reflecting telescope, which actually predated Newton’s and it was the Gregorian that, principally in the hands of James Short, became the dominant model in the eighteenth century. Although to be fair one should mention that William Herschel made his discoveries with Newtonians. Once again our author’s claim fails to hold water.

Sticking with optics for the moment it is a little know and even less acknowledge fact that the Bohemian physicus and mathematician Jan Marek Marci (1595 – 1667) actually decomposed white light into its constituent colours before Newton. Remaining for a time with optics, James Gregory, Francesco Maria Grimaldi, Christian Huygens and Robert Hooke were all on a level with Newton although none of them wrote such an influential book as Newton’s Optics on the subject. Now this was not all positive. Due to the influence won through the Principia, The Optics became all dominant preventing the introduction of the wave theory of light developed by Huygens and Hooke and even slowing down its acceptance in the nineteenth century when proposed by Fresnel and Young. If Newton hadn’t been born optics might even have developed and advance more quickly than it did.

This just leaves the field of classical mechanics Newton real scientific monument. Now, as I’ve pointed out several times before the three laws of motion were all borrowed by Newton from others and the inverse square law of gravity was general public property in the second half of the seventeenth century. Newton’s true genius lay in his mathematical combination of the various elements to create a whole. Now the question is how quickly might this synthesis come about had Newton never lived. Both Huygens and Leibniz had made substantial contribution to mechanics contemporaneously with Newton and the succeeding generation of French and Swiss-German mathematicians created a synthesis of Newton’s, Leibniz’s and Huygens’ work and it is this that is what we know as the field of classical mechanics. Without Newton’s undoubtedly massive contribution this synthesis might have taken a little longer to come into being but I don’t think the delay would have radically changed the world in which we live.

Like almost all great scientists Newton’s discoveries were of their time and he was only a fraction ahead of and sometimes even behind his rivals. His non-existence would probably not have had that much impact on the development of history.

Moving on to Gauss we will have other problems. Our author again makes a good start:

Isaac Newton is a hard act to follow, but if anyone can pull it off, it’s Carl Gauss. If Newton is considered the greatest scientist of all time, Gauss could easily be called the greatest mathematician ever.

Very hyperbolic and hagiographic but if anybody could be called the greatest mathematician ever then Gauss would be a serious candidate. However in the next paragraph we go off the rails. The paragraph starts OK:

Carl Friedrich Gauss was born to a poor family in Germany in 1777 and quickly showed himself to be a brilliant mathematician. He published “Arithmetical Investigations,” a foundational textbook that laid out the tenets of number theory (the study of whole numbers).

So far so good but then our author demonstrates his lack of knowledge of the subject on a grand scale:

Without number theory, you could kiss computers goodbye. Computers operate, on a the most basic level, using just two digits — 1 and 0

Here we have gone over to the binary number system, with which Gauss book on number theory has nothing to do, what so ever. In modern European mathematics the binary number system was first investigated in depth by Gottfried Leibniz in 1679 more than one hundred years before Gauss wrote his Disquisitiones Arithmeticae, which as already stated has nothing on the subject. The use of the binary number system in computing is an application of the two valued symbolic logic of George Boole the 1 and 0 standing for true and false in programing and on and off in circuit design. All of which has nothing to do with Gauss. Gauss made so many epochal contributions to mathematics, physics, cartography, surveying and god knows what else so why credit him with something he didn’t do?

Moving on to John von Neumann we again have a case of credit being given where credit is not due but to be fair to our author, this time he is probably not to blame for this misattribution.  Our author ends his von Neumann description as follows:

Before his death in 1957, von Neumann made important discoveries in set theory, geometry, quantum mechanics, game theory, statistics, computer science and was a vital member of the Manhattan Project.

This paragraph is fine and if Shea Gunther had chosen to feature von Neumann’s invention of game theory or three valued quantum logic I would have said fine, praised the writer for his knowledge and moved on without comment. However instead our author dishes up one of the biggest myths in the history of the computer.

he went on to design the architecture underlying nearly every single computer built on the planet today. Right now, whatever device or computer that you are reading this on, be it phone or computer, is cycling through a series of basic steps billions of times over each second; steps that allow it to do things like render Internet articles and play videos and music, steps that were first thought up by John von Neumann.

Now any standard computer is called a von Neumann machine in terms of its architecture because of a paper that von Neumann published in 1945, First Draft of a Report on the EDVAC. This paper described the architecture of the EDVAC one of the earliest stored memory computers but von Neumann was not responsible for the design, the team led by Eckert and Mauchly were. Von Neumann had merely described and analysed the architecture. His publication caused massive problems for the design team because the information now being in the public realm it meant that they were no longer able to patent their innovations. Also von Neumann’s name as author on the report meant that people, including our author, falsely believed that he had designed the EDVAC. Of historical interest is the fact that Charles Babbage’s Analytical Engine in the nineteenth century already possessed von Neumann architecture!

Unsurprisingly we walk straight into another couple of history of the computer myths when we turn to Alan Turing.  We start with the Enigma story:

During World War II, Turing bent his brain to the problem of breaking Nazi crypto-code and was the one to finally unravel messages protected by the infamous Enigma machine.

There were various versions of the Enigma machine and various codes used by different branches of the German armed forces. The Polish Cipher Bureau were the first to break an Enigma code in 1932. Various other forms of the Enigma codes were broken by various teams at Bletchley Park without Turing. Turing was responsible for cracking the German Naval Enigma. The statement above denies credit to the Polish Cipher Bureau and the other 9000 workers in Bletchley Park for their contributions to encoding Enigma.

Besides helping to stop Nazi Germany from achieving world domination, Alan Turing was instrumental in the development of the modern day computer. His design for a so-called “Turing machine” remains central to how computers operate today.

I’ve lost count of how many times that I’ve seen variations on the claim in the above paragraph in the last eighteen months or so, all equally incorrect. What such comments demonstrate is that their authors actually have no idea what a Turing machine is or how it relates to computer design.

In 1936 Alan Turing, a mathematician, published a paper entitled On Computable Numbers, with an Application to the Entscheidungsproblem. This was in fact one of four contemporaneous solutions offered to a problem in meta-mathematics first broached by David Hilbert, the Entscheidungsproblem. The other solutions, which needn’t concern us here, apart from the fact that Post’s solution is strongly similar to Turing’s, were from Kurt Gödel, Alonso Church and Emil Post. Entscheidung is the German for decision and the Entscheidungsproblem asks if for a given axiomatic system whether it is also possible with the help of an algorithm to decide if a given statement in that axiom system is true or false. The straightforward answer that all four men arrived at by different strategies is that it isn’t. There will always be undecidable statements within any sufficiently complex axiomatic system.

Turing’s solution to the Entscheidungsproblem is simple, elegant and ingenious. He hypothesised a very simple machine that was capable of reading a potentially infinite tape and following instruction encoded on that tape. Instruction that moved the tape either right or left or simply stopped the whole process. Through this analogy Turing was able to show that within an axiomatic system some problems would never be Entscheidbar or in English decidable. What Turing’s work does is, on a very abstract level, to delineate the maximum computability of any automated calculating system. Only much later, in the 1950s, after the invention of electronic computers a process in which Turing also played a role did it occur to people to describe the computational abilities of real computers with the expression ‘Turing machine’.  A Turing machine is not a design for a computer it is term used to described the capabilities of a computer.

To be quite open and honest I don’t know enough about Benoit Mandelbrot and fractals to be able to say whether our author at least got that one right, so I’m going to cut him some slack and assume that he did. If he didn’t I hope somebody who knows more about the subject that I will provide the necessary corrections in the comments.

All of the errors listed above are errors that could have been easily avoided if the author of the article had cared in anyway about historical accuracy and truth. However as is all to often the case in the history of science or in this case mathematics people are prepared to dish up a collection of half baked myths, misconceptions and not to put too fine a point on it crap and think they are performing some sort of public service in doing so. Sometimes I despair.



Filed under History of Computing, History of Logic, History of Mathematics, History of Optics, History of Physics, History of science, Myths of Science, Newton

Killed by Homeopathy

The mathematician, philosopher and logician George Boole died on the 8th December 1864. What most people don’t realise is that he was in all probability killed by homeopathy.


Georg Boole c. 1860 Source: Wikimedia Commons

In 1849 Boole, a self-taught mathematician and school master, was appointed Professor of Mathematics at the newly founded Queen’s College Cork and it was here in 1850 that he first met Mary Everest, niece of the military surveyor Colonel George Everest after whom the mountain is named, who was visiting another of her uncles, John Ryall who was Professor of Greek at Cork.  The family name, by the way, is pronounced Eve – rest and not Ever – rest. From 1852 on George became Mary’s maths tutor and when her father died in 1855 the two of them married. Despite a fairly large difference in age it was a happy marriage that produced five rather special daughters, who I might blog about another time.


Mary Everest Boole Source: Wikimedia Commons

Mary Everest Boole was a highly intelligent woman who after the death of her husband, she lived for another 52 years, would go on to become a noted educationalist who today is something of a feminist icon. She had, however, at least one fatal flaw. Mary’s father had been a devoted disciple of Samuel Hahnemann and she spent a large part of her childhood living in Hahnemann’s house in France where she too became an adherent of his medical philosophy.


Samuel Hahnemann

The Boole’s lived outside of Cork and one day when walking home from work George got drenched in a downpour and developed a chill. Mary following Hahnemann’s guiding principle that “like cures like” wrapped her ailing husband in wet bed sheets. George developed pneumonia and died. This story is not based on hearsay or a popular myth but the written testimony of one of their daughters who never forgave her mother for having, in her opinion, killed her father.

The next time somebody tells you that homeopathy is harmless you can tell them that it killed one of the greatest mathematical minds of the nineteenth century on whose algebraic logic both the soft- and the hardware of your computer function.


Filed under History of Logic, History of Mathematics, History of science

Cantor Redux

I got criticised on my twitter stream for the Cantor article I posted yesterday. I was not called to order for being to harsh, @ianppreston criticised me, quite correctly, for not being harsh enough! As I don’t wish to create the impression that I’m becoming a wimp in my old age I thought I would give Ms Inglis-Arkell another brief kicking.

Strangely my major objection from yesterday has mysteriously disappeared from her post (did somebody tip her off that she was making a fool of herself?) but there remains enough ignorance and stupidity to amuse those with some knowledge of Cantorian set theory and transfinite arithmetic, knowledge, which Ms Inglis-Arkell apparently totally lacks.

Ms Inglis-Arkell’s dive into the depths of advance mathematics starts so:

Imagine a thin line, almost a thread, stretching to infinity in both directions. It runs to the end of the universe. It is, in essence, infinite. Now look at the space all around it. That also runs to the end of the universe. It’s also infinite. Both are infinite, yes, but are they the same? Isn’t one infinity bigger than the other?

 The answer to the second question is actually no! Cantor demonstrated, counter-intuitively, that the number of points on a straight, the number of points in a square and the number of points in a cube are all infinite, all equal and all equal to ‘c’ the cardinality of the real numbers and the power set of aleph-nought.

After defining the infinite number of natural numbers as aleph-nought Ms Inglis-Arkell then writes the following:

But then what about real numbers? Real numbers include rational numbers, and irrational numbers (like the square root of five), and integers. This has to be a greater infinite number than all the other infinite numbers.

 These three sentences contain three serious errors, one implied and two explicit. The rational numbers includes the integers so to state them separately when describing the real numbers is either wrong or at best tautologous. Secondly, and this is the implicit mistake, a set consisting of the rational numbers and those irrational numbers, which are also algebraic numbers i.e. describable with an algebraic equation for example X2 = 2, is also a countable infinite set that is equal to aleph-nought. Only when one includes the so called transcendental irrational numbers, those that cannot be described with an algebraic equation for example the circle constant π, that the infinite set become larger than aleph-nought. This result is again extremely counter-intuitive, as very few transcendental numbers have ever been identified. The final error is very serious because the cardinal number of the real numbers ‘c’ (for continuum) is by no means “a greater infinite number than all the other infinite numbers.

Cantor could demonstrate that the so-called power set of an infinite set, i.e. the set of all the subsets of the set, has a larger cardinality than the set itself. This newer set also has a larger power set and so on ad infinitum. As stated above c is equal to the power set of aleph-nought. There is in fact an infinite hierarchy of infinite sets each one larger than its predecessor. On of the great mysteries of Cantorian set theory is where exactly c fits into this hierarchy. Cantor asked the question whether c is equal to aleph-one where aleph-one is defined as the the cardinality of the set of all countable ordinal numbers (1)? He himself was not able to answer this question. It later turned out that it is in fact an undecidable question. In the axiomatic version of Cantorian set theory, the theory is consistent, i.e. free of contradictions, both when c is assumed to be equal to aleph-one and when they are assumed to be not equal. This produces two distinct set theories, the first with c equal to aleph-one is called Cantorian the other non-Cantorian.

Although my sketch of Cantorian set theory and transfinite arithmetic is only very basic I hope I have said enough to show that it is really not a subject about which one should write if, as appears to be the case with Ms Inglis-Arkell, one doesn’t have the necessary knowledge.

(1) Going beyond this and explaining exactly what this means goes futher than is healthy in normal life. For those who are curious I recommend Rudy Rucker’s Infinity and the Mind, Birkhäuser, 1982

Later additions: I have corrected the mistakes kindly pointed out by Sniffnoy in the comments. Note to self: Turn brain on before skating on the thin ice of transfinite arithmetic.


Filed under History of Logic, History of Mathematics

The Cult of St Alan of Bletchley Park

I realise that to rail against anything published in the Daily Fail is about as effective as pissing against the wind in a force 8 gale but this article on Alan Turing got so up my nose that I have decided to strap on my bother-boots of historical criticism and give the author a good kicking if only to assuage my own frustration. It won’t do any good but it might make me feel better.

Before I start in on a not so subtle demolition job, I should point out that I’m actually a Turing fan who has read and absorbed Andrew Hodges’ excellent Turing biography[1] as well as many books and articles on and by Turing. I have seriously studied his legendary paper on the Entscheidungsproblem[2], I have a copy sitting on my bookshelf, which I understand thoroughly including its significance for Hilbert’s Programme, which the Mail’s journalist almost certainly does not. If I here seem to be seriously challenging Turing’s claims to scientific sainthood it is only in the interests of historical accuracy and not out of any sense of antipathy to the man himself, who would definitely be one of my heroes if I went in for them.

The Mail article opens with a real humdinger of a claim that is so wrong it’s laughable:

Own a laptop, a smartphone or an iPad? If so, you owe it to a man many of us have never heard of – a genius called Alan Turing. ‘He invented the digital world we live in today,’ says Turing’s biographer David Leavitt in a new Channel 4 drama-documentary about the brilliant mathematician.

Sorry folks Alan Turing did not invent the digital world we live in today. In the 1930s Turing was one of several meta-mathematicians who laid the theoretical foundations for computability and although his contributions were, viewed from a technical standpoint, brilliant we would still have had the computer revolution if Alan Turing as an undergraduate had turned his undoubted talents to deciphering ancient Sumerian clay tablets instead of to solving meta-logical problems. The German computer pioneer Konrad Zuse designed and built functioning digital computers in the 1930s and 40s without, as far I know, ever having heard of Turing. Zuse was an engineer and not a mathematician and approached the problem from a purely practical point of view. The American engineer Vannevar Bush built a highly advanced analogue computer, his Differential Analyser, to solve differential equations in 1927 when Turing was still at school. Claude Shannon who laid the foundations of digital circuit design was one of Bush’s graduate students. All three American groups, which developed digital computers in the late 193os and early 1940s, Atanasoff and Berry in Iowa, Aiken in Harvard and Eckert and Mauchly in Pennsylvania all referenced Bush when describing their motivations saying they wished to construct an improved version of his Differential Analyser. As far as I know none of them had read Turing’s paper, which is not surprising as Turing himself claimed that in the 1930’s only two people had responded to his paper. The modern computer industry mainly developed out of the work of these three American groups and not from anything produced by Turing.

Turing did do work on real digital computers at Bletchley Park in the 1940s but this work was kept secret by the British government after the war and so had no influence on the civil development of computing in the 1950s and 60s. Turing like many other of the computer pioneers from Bletchley started again from scratch after the war but due to their delayed start and underfunding they never really successfully competed with the Americans. We now turn to Bletchley Park and Turing’s contribution to the Allied war effort. The Mail writes:

Ironically, the same society that hounded him to his death owed its survival to him. For during the Second World War it was Turing who pioneered the cracking of Nazi military codes at Bletchley Park, allowing the Allies to anticipate every move the Germans made.

The first sentence is a reference to Turing’s suicide caused by his mistreatment as a homosexual, which I’m not going to discuss here other than to say that it’s a very black mark against my country and my countrymen. We now come to a piece of pure hagiography. The cracking of the Germany military codes was actually pioneered by the Poles before Bletchley Park even got in on the act. It should also be pointed out that Turing was one of nine thousand people working in Bletchley by the end of the War. Also he was only in charge of one team working on one of the codes in use, the navel naval Enigma, there were several other teams working on the other German codes. Turing was one cog in a vast machine, an important cog but a long way from being the whole show. The Mail next addresses Turing’s famous paper:

‘While still a student at Cambridge he wrote a paper called Computing Machinery, in which all the developments of modern computer science are foretold. If you take an iPhone to pieces, all the parts in there were anticipated by Turing in the 1930s.’

He wasn’t a student but a postgraduate fellow of his college. The title of the paper is On Computable Numbers, with an Application to the Entscheidungsproblem. It outlines some of the developments of modern computing but not all and no he didn’t anticipate all of the parts of an iPhone. Apart from that the paragraph is correct.

Turing’s outstanding talents were recognised at the outbreak of war, when he was plucked from academic life at Cambridge to head the team at Bletchley Park, codenamed Station X. They were tasked with breaking the German codes, transmitted on complex devices called Enigma machines, which encrypted words into as many as 15 million million possible combinations.

‘Turing took one look at Enigma and said, “I can crack that,”’ says Sen. ‘And he did.’ Part of Turing’s method was to develop prototype computers to decipher the Enigma codes, enabling him to do in minutes what would take a team of scientists months to unravel. It was thanks to him that the movements of German U-boats could be tracked and the battle for control of the Atlantic was won, allowing supplies to reach Britain and saving us from starvation.

Turing was not “plucked from academic life”; interested in the mathematics of cryptology Turing started working for the Government Code and Cypher School already in 1938 and joined the staff of Bletchley Park at the outbreak of war. The department he headed was called Hut 8. With reference to the computers developed in Bletchley, as I have already said in an earlier post Turing was responsible for the design of special single purpose computer, the Bombe, which was actually a development from the earlier Polish computer the Bomba and had nothing to do with the much more advance and better known Bletchley invention, the Colossus. The second paragraph is largely correct.

The life and work of Alan Turing and the role of Bletchley Park in the war effort are both important themes in the histories of science, mathematics and technology and can certainly be used as good examples on which to base popular history but nobody is served by the type of ignorant, ill-informed rubbish propagated by the Daily Fail and obviously by the Channel 4 documentary that they are reporting on, which is obviously being screened tonight. My recommendation don’t watch it!


[1] Andrew Hodges, Alan Turing: The Enigma, Simon & Schuster, 1983.

[2] Alan M. Turing, On Computable Numbers, with an Application to the Entscheidungsproblem, Proceedings of the London Mathematical Society, 2 ser. vol. 42, (1936 – 37), pp. 230 – 265.


Filed under History of Computing, History of Logic, History of Mathematics

A lover of paradoxes

As I have probably mentioned more than once I served my apprenticeship as a historian of science working in a research project on the history of formal or symbolic logic. My special area within the project was British logical algebra in the 19th century and it was here that I took a long deep look at Augustus De Morgan who was born in Madurai in the Madras Presidency, an administrative sub-division of British India on the 27th June 1806. De Morgan was a brilliantly eclectic polymath with a Pythonesque sense of humour who both from his personality and from his appearance seemed to spring out of Charles Dickens’ Pickwick Papers, a mathematical second cousin to Sam Weller. De Morgan is my favourite Victorian.


Augustus De Morgan Source: Wikimedia Commons

Son of an army officer in the service of the East India Company he moved to England whilst only seven months old. At the age of sixteen he went up to Trinity College Cambridge where he quickly became part of the circle around George Peacock and William Whewell who would stimulate his life long interest in mathematics and logic. In 1826 he graduated 4th Wrangler in the mathematical tripos but already a convinced Unitarian he refused to sign the religious declaration required in Oxbridge in those days to graduate MA and so was not eligible for the fellowship for which he would normally have been destined. He went instead to London to study for the bar. However he found law boring and at the age of 21 and with no publication to his name he applied for the chair of mathematics at the newly founded University College London. This new university had been founded by a group of social reformers who felt that a university education should be open to all what ever their religious belief might be, Oxbridge only being open to confirmed Anglicans. Despite his youth and lack of experience De Morgan was appointed University College’s first professor of mathematics in 1828. He resigned the post only three years later on a mater of principle but was reappointed in 1836 and remained professor until 1866 when he again resigned on another mater of principle.

That De Morgan should be identified with an institution of social reform was not a mater of chance and social reform defined much of his life. He became professor of mathematics at the newly founded Queen’s College an institute of higher education for women founded by Frederick Denison Maurice. Most notably he was a highly active member of the Society for the Diffusion of Useful Knowledge an organisation dedicated to making scientific and other knowledge available in cheap, clear and concise printed versions written by the best authors. De Morgan was the most prolific of all the SDUK authors and wrote and published books and articles on a bewildering range of topics. Another of his social reformers contacts was the Unitarian William Frend whose daughter Sophia would become De Morgan’s wife.

De Morgan devoted part of his academic efforts to the reform and modernisation of formal logic, a subject that had been in a sort of coma in England for about three hundred years before being awakened from its slumbers by Richard Whately at the beginning of the 19th century. De Morgan who worked in the traditional syllogistic Aristotelian logic introduced the concept of quantification of the predicate enabling logically conclusion not possible in the traditional logic. This invention led to a bitter dispute with the Scottish philosopher Sir William Hamilton (not to be confused with the Irish mathematician Sir William Hamilton, a good friend of De Morgan’s) who claimed priority for this logical discovery. This dispute attracted the attention of another mathematician, George Boole, who stimulated by the discussion developed his algebraic logic. Boole and De Morgan were not only both disciples of the algebraic innovation of George Peacock and logical pioneers but shared a Unitarian religious outlook and became lifelong friends. De Morgan was especially proud of the fact that his Formal Logic and Boole’s Mathematical Analysis of Logic were published on the same day in 1847. Introducing, in his opinion, a new age in logic. In reality De Morgan was incorrect as the two books were published about a week apart. Although De Morgan’s logical work was by no means as innovative as Boole’s he was the first modern logician to work on the logic of relation an area that was later developed by Charles Sanders Peirce in America and Ernst Schröder in Germany both of whom were great admirers of De Morgan.

De Morgan made significant contributions to many areas of mathematics but his principle achievements were in trigonometry and in abstract algebras. His most lasting contribution was the formalisation of the principle of mathematical induction, an important tool in mathematical proof theory, to which he also contributed the name. Strangely he is best remembered today for De Morgan’s Laws. This is peculiar because the laws were not discovered by De Morgan but had been known both to Aristotle and the mediaeval logicians; De Morgan merely made them better known. The laws are fairly trivial “not (A or B) is equal to not A and not B” and “not (A and B) is equal to not A or not B” but very useful in deductive logical proofs.

De Morgan also made important contributions to the history of science. The Scottish physicist David Brewster wrote and published the first modern English biography of Isaac Newton largely as a reaction to the English translation of the biography by the French physicist Jean – Baptiste Biot, which had been published by the SDUK. De Morgan didn’t like what he saw as Brewster’s Newton hagiography and wrote and published a series of biographical pamphlets on Newton, correcting what he saw as Brewster’s errors. This led to a literary dispute between the two men with both of them digging deeper and deeper into the original sources, Newton’s letters, papers, notebooks etc., in order to prove the correctness of their Newton picture. This development led scientific biography away from literary hagiography towards modern historiography. For the full details of these developments I recommend the very readable account by Rebekah Higgitt in her excellent Recreating Newton.

De Morgan also wrote and published his Arithmetical Books in which he discussed the work of over 1500 authors on the subject. This book is still regarded as an important source in the history of mathematics.

I said that De Morgan had a Pythonesque sense of humour and his letters, papers and notebooks are full of wonderful whimsies. His most famous book is his Budget of Paradoxes.


De Morgan collected the written products of circle squarers and other mathematical fools who he then exposed to ridicule in a series of newspaper articles. These were collected in a book and published after his death. This gem is still in print and is a secret tip amongst philosophers, mathematicians and logicians.

Unlike many of his friends and contemporaries De Morgan was not very active in the numerous scientific societies that flourished in the 19th century. He refused membership of the Royal Society on grounds of principle because he saw it as an elitist organisation. The only society of which he was a member was the Astronomical Society. However when his son George, like his father a gifted mathematician, founded the London Mathematical Society De Morgan became its first President.

De Morgan was a fascinating and stimulating polymath who certainly deserves to be better known than he is. One way you can do that is by getting hold of a copy of the very readable Memoir of Augustus De Morgan by his wife Sophia Elizabeth De Morgan.



Filed under History of Logic, History of Mathematics, History of science

Ich bin ein Gastbloggerin: A special post for International Women’s Day.

My fellow guest blogger Penny Richards wrote in her post on Joyce Kaufman:

Although Johns Hopkins didn’t welcome women students in those days

To celebrate International Women’s Day I thought I would draw the readers’ attention to another earlier women scientist who suffered under the negative attitude to women of Johns Hopkins University. To find out who go here

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Filed under History of Logic, History of Mathematics