A letter La Bastide – van Gemert didn’t forge

This is a very serious issue. Nothing to laugh about. Which reminds me that humour is a serious issue too. One problem in this discussion about Pierre and Dina van Hiele – Geldof and Hans Freudenthal is that participants may not laugh enough. It is a dirty math war and no fun. Slinging mud and no throwing of cakes with whipcream. I consulted my source on this, professor of humour Art Buchwald. He advised: “When you try to be funny try to remember that people should laugh.”

Readers may lose sight of what the issue is. Too many texts. Do you still remember it ? Some didactics may be required. A picture tells more than a thousand words.

It was already necessary to explain that Hans Freudenthal is no demon. I never said or implied that he would be a demon, but somehow people like to demonize. It will also be useful to explain that Sacha la Bastide – van Gemert is no demoness. Both are mere fallible human beings. When both are treated with respect then all will be well. Some misunderstandings will be cleared and some errors repaired.

Below I will show the problematic email exchange with LB-VG of 2014. The exchange is in Dutch, and thus I provide an independent Google Translation too, so that you can ask your Dutch friends what the fun language actually means. Hopefully the MAA provides for independent translation.

The problem is that LB-VG said that she did not have time (“now”) to look into the inconsistency that I spotted in her thesis: yet, in 2015 she put out an English translation ? For all I know the inconsistency is still there, now for a larger audience (the world). It is not just that she took me for a walk in the woods and left me there. It is also that she provided English readers (the world) with a text that she knew (had been alerted to) was problematic. And indeed, when we look closer at the source that she had (the Euclides article of 1957), then her treatment is even more problematic: see here.

On the bright side: LB-VG did not forge data like Diederik Stapel.

It will be didactical to first look at what she didn’t do and then at what she did do.

LB-VG didn’t forge this letter

Let us first look at the letter that LB-VG didn’t forge. We can stamp it with the “Uncle Hans is watching you” poster that we discovered from some fans in an earlier weblog. Do not forget to check out the website of Raymond Johnson at the Freudenthal Institute USA, who is closely tracking issues for criticism that he wants to neglect.

Forged letter of April 1 1957

Forged letter of April 1 1957, True poster by Dr Bote September 8 2013

The importance of not-forging this letter by LB-VG is:

  1. She doesn’t have to forge letters when she can achieve the same end by including an inconsistency in her thesis, and not looking into this when she is alerted to this, and then translate it into English. The thesis may portray Freudenthal as a hero and not a crook.
  2. She may actually have looked into the question on the inconsistency, and decided that in her mind there was no inconsistency, so that she thought that she honestly could proceed with the English translation. She only forgot, or simply didn’t have time, to inform me about this check-up and decision of hers. Why should she inform me ? I am just another scientist asking a question, and there are so many other scientists and other people asking questions. (The problem with answering a question is that this may cause new questions, in particular when you don’t really answer the question.)
  3. She may have reasoned that the thesis was accepted in 2006, so that the English translation should be about that accepted thesis as it is. This would reflect the true state of affairs of 2006, with scientific backing by thesis supervisors Karel van Berkel and Jan van Maanen (and others in the committee). Any discussion about new questions could happen after putting out the translation.

Point 1 shows the didactic power of the forged letter: it captures what is happening, and how hero worship may make people blind to hero error.

Point 2 would confirm the incompetence, and also that she may not have known enough about the Van Hiele level theory (though misreading statements that are very clear). Perhaps the thesis was overambitious, with too many topics, or the lure too great of including the level theory as another feat by Freudenthal ?

Point 3 would be self-serving. It is an argument by a lawyer, not a scientist.

PM. After LB-VG stated not to have time, I did query these other people involved with the thesis. They declined interest in the same manner, see later publications of emails.

The LB-VG statement in 2014 that she didn’t have time

It will be useful to start with the shortest email. The Dutch original:

From: Bastide-van Gemert, S la
To: Thomas Cool / Thomas Colignatus
Subject: RE: N.a.v. uw proefschrift, Hoofdstuk 7, Van Hiele niveaux
Date: Tue, 19 Aug 2014

Geachte mijnheer Cool,

Dank voor uw e-mail. Ik heb nu helaas geen mogelijkheid inhoudelijk te reageren, maar wens u veel succes met uw artikel.

Met vriendelijke groet,

Sacha la Bastide

Google Translate actually gives a rather fair translation. It curiously eliminates the “now” (Dutch “nu”). In Dutch, LB-VG still leaves me hope that she will look into it later.

Dear Mr. Cool,

Thanks for your email. I have unfortunately no opportunity to respond to the content, but wish you much success with your article.


Sacha la Bastide

Observe that emails from the University Medical Center Groningen (UMCG) come with the following disclaimer, which is inappropriate to include in this kind of scientific exchange:

“The contents of this message are confidential and only intended for the eyes of the addressee(s). Others than the addressee(s) are not allowed to use this message, to make it public or to distribute or multiply this message in any way. The UMCG cannot be held responsible for incomplete reception or delay of this transferred message.” (Included in the LB-VG email)

My email of 2014 that asked about the inconsistency

Dutch original:

Van: Thomas Cool / Thomas Colignatus
Verzonden: 19 August 2014
Aan: Bastide-van Gemert, S la
Onderwerp: N.a.v. uw proefschrift, Hoofdstuk 7, Van Hiele niveaux

Geachte dr. La Bastide – Van Gemert,

Heeft u nog interesse in uw proefschrift, of bent u doorgegaan naar nieuwe terreinen, zoals de epidemiologie ?

N.a.v. de situatie in het onderwijs in wiskunde en rekenen kwam ik ertoe ook te kijken naar de invloed van Hans Freudenthal.

Relevant leken daartoe ook de herinneringen van David Tall, een Engelsman. Toen ik hem e.e.a. navroeg begon hij ook over Pierre van Hiele en zijn eigen jongste boek (2013).

E.e.a. leidde tot dit artikel, beoogd voor een tijdschrift:


Uw Hoofdstuk 7 bespreek ik op p7-8. Mijn conclusie is dat u eigenlijk inconsistent bent, wanneer de Van Hieles in 1957 in Euclides al een algemene geldigheid voor hun theorie claimen, door u geciteerd, en u tegelijkertijd stelt dat Freudenthal dat pas aanbracht. M.i. heeft u dan een roze bril t.a.v. Freudenthal gehad, en niet doorgehad wat hier allemaal gebeurde. Per saldo kom ik tot de conclusie dat niet alleen Freudenthal maar nu ook David Tall een neiging hadden / hebben om Van Hiele in het hokje van de meetkunde te plaatsen, terwijl de Van Hieles juist in relatie tot Piaget een algemene theorie presenteerden met meetkunde slechts als voorbeeld.

Ik houd me aanbevolen voor een reactie.

Met vriendelijke groet,

Thomas Cool / Thomas Colignatus
Econometrist en leraar wiskunde

Google Translate, perhaps as curious as the letter that LB-VG didn’t forge, but with the same idea.

From: Cool Thomas / Thomas Colignatus
Sent: 19 August 2014
To: Bastide-van Gemert, S la
Topic: N.a.v. your thesis, Chapter 7, Van Hiele niveaux

Dear Dr La Bastide -. Van Gemert,

If you have any interest in your dissertation, or are you moved on to new areas such as epidemiology?

N.a.v. the situation in education in mathematics and arithmetic I committed came to look at the influence of Hans Freudenthal.

Relevant to this end also seemed the memories of David Tall, an Englishman. When I queried him eea he started about Pierre van Hiele and his most recent book (2013).

E.e.a. led to this article, intended for a magazine:


Your Chapter 7, I discuss on p7-8. My conclusion is that you are actually inconsistent, when the Van Hiele in 1957 in Euclid already claiming a universal validity for their theory, you quoted, and you set it at the same time that it was only put in Freudenthal. MFI you then have a rose-tinted glasses had Attn Freudenthal, not by what had happened here. On balance, I come to the conclusion that not only Freudenthal but now David Tall had a tendency / have to Van Hiele in the box to place the geometry, while the Van Hiele’s right in relation to Piaget presented a general theory to geometry just as example.

I love to hear a response.


Cool Thomas / Thomas Colignatus
Econometrician and math teacher


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