In October, the African edition of the *Conversation, *carried an article by Karen Brodie, on the decolonisation of mathematics, which asserted, “Much, though certainly not all, of mathematics was created by dead white men." That false history was used for centuries by numerous reputable Western philosophers, such as Hume and Kant, to assert the non-creativity of blacks, and to morally justify racism and slavery. Likewise, Macaulay used the very same false history to assert the non-creativity of the non-West in science, and to impose colonial education, essential to create a slave mentality to offset the military weakness of the British.

To contest racism and colonialism I challenged this argument in my article “To decolonise math, stand up to its false history and bad philosophy”, published on the *Conversation* on October 24. My article went viral and got 16,737 readers before it was suddenly taken down two days later. (For reference, it has now been re-posted on my blog.) *[Editor's note: Scroll.in had republished the article from The Conversation and pulled it from the site after the original source of the piece retracted it.]*

The editors did not point to a single error of fact or argument. Had there been any error, they could have easily published a rejoinder. Instead, the editor (Africa), Caroline Southey, appealed to “editorial reasons” to take down the article. "You have sited [sic] only your own work to back up your key points," she said. Had this really been true, the *Conversation* would have indicated a willingness to re-post the article if some more references are cited.

In fact, the exact editorial reason is not stated publicly just because that would immediately expose the falsehood of the excuse given. Simply examine the article: it cites Karen Brodie, it cites Clagett’s Egyptian source book for the Rhind papyrus, it cites the *Principia* of Whitehead and Russell, it cites the book on *Decolonising the University* by Claude Alvares and Shad Faruqi. Further, one of the citations is to some 22 clips archived from the *Sun*, Malaysia. This followed an editorial written by its late chief editor on my talk, and also archives much material written by others against me. The link to the blog is just a compact way of referencing that material: a compactness essential for the format used by *Conversation*.

### Practical problems

Clearly, Southey did not check facts, even about citations, or is deliberately twisting them. Again, since the *Conversation* allows only hyperlinks, and no hyperlink was available to a 1572 document, I cited my book which cites that document, as I earlier explained to another editor before the article was published. My article cites newspaper articles and interviews. A newspaper or magazine article which concerns me, is nevertheless work done by others. One such news report was critical of me. It is decidedly dishonest to call it a self-citation as Southey does (though only in private).

Further, I had to cite my past work on decolonisation of math to point out how much of it Brodie missed. Failing to cite past work is apparently quite up to the academic standards of the *Conversation, *but correcting it is not. Whose work should I have cited to bring out that omission? Anyway, no one I know worked earlier on the decolonisation of math and hard science. Is it a crime to do pioneering work? That is, in inventing new rules, the editor conflated academic standards with status quo, which is what decolonisation challenges.

Hiding the editorial reasons also serves to insinuate. Obviously, the real reason to take down the article was to suppress an inconvenient truth through censorship. In fact, 15 years ago, the leading Western expert on Greek mathematics, David Fowler, publicly admitted that nothing is known about Euclid. This was in response to my intervention on the Historia Matematica mailing list. My Euclid challenge prize of Rs 2 lakh, which stands unclaimed for six years, was intended to demonstrate that this faith-based history of Greek glorification is too flimsy to survive without editorial controls and censorship.

Though attention was focused on false history, the most dangerous part of my article concerned the *practical* and contemporary consequences: rejecting bad Western philosophy leads to a better math and science. While bad Western metaphysics is *politically* useful, as a tool to create epistemic dependence, and a slave mentality, that can negatively affect the practical applications of math. As a non-technical example, I gave the (Western understanding of the) “Pythagorean theorem”. Because that celebrated “infallible truth” is actually invalid knowledge, for triangles drawn on earth, it led to centuries of navigational disasters in Europe. Some people did not get the point: they argued that it was valid but approximate knowledge. But if it is only approximate knowledge, as Bhaskar too asserted, we need to *calculate *the *degree* of approximation.

### Different understandings

This was possible in the Iraqi, Egyptian, and Indian traditions, where the Pythagorean proposition was understood *differently.* It was stated for the diagonal of a rectangle, and was used to *calculate* (a) the diagonal (given the sides, which requires square roots) or *calculate* (b) the sides, given the diagonal and one angle (as in navigation; this requires sine values). That math was about approximate *calculation*, not proof, as is *all* practical math. The Manava *sulba sutra* explicitly states the Pythagorean proposition using square *roots. *Though, more accurate values of* * are found in Iraq and Egypt, the philosophy survives only in the Indian tradition which explicitly states that this knowledge is *inexact* and *non-eternal*. But that makes deductive proofs useless; and, as for calculation, the West did not learn about square roots until after the 12th c., as the very word “surd” shows.

Further, as Brahmagupta remarked, it is futile to calculate longitude without knowing the earth’s radius accurately. He calculated it, as did Khalifa al Mamun, and it was probably known long before that in Egypt. That calculation however, requires knowledge of sine values, a key part of the “Pythagorean calculation”, not known to the West, as the very word “sine” shows. The correct radius of the earth was *hence* not known to Columbus, and not known to Clavius, even after he published trigonometric tables to ten decimal place precision, in 1608 (obviously stolen from India). This exposes the Western *lack of understanding* of the “Pythagorean calculation”: not only was there no Pythagoras, nor any deductive proof of the proposition, alas, the West did not know how to make serious practical calculations using that proposition, until the late 17th c.

Of course, rejecting the redundant metaphysics of math, such as Whitehead and Russell’s 378 page proof of 1+1=2, makes math very easy and is sure to make millions of students very happy. Likewise rejecting the creep of Newton’s metaphysics, into his physics, through calculus, corrects both Newtonian physics and gravitation. More examples, involving the bad metaphysics of infinity, are mentioned in the video and abstract of my MIT talk, and reading list, already cited in the original article. This failure of the West to understand even science, because of bad metaphysics, will once and for all kill the story of Western superiority. Hence, dishonest editors stand in the way, as the gatekeepers of bad knowledge, trying desperately to save Western “soft power”.

*More of Chandra Kant Raju's work can be read on his website.*

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