Scharf, Lotte

May 26, 2021

33. How is current knowledge shaped by its historical development?

Object 1: Rosalind Franklin’s X-ray diffraction of DNA


This picture shows the first defining photo of a DNA strand taken by X-ray diffraction. It enriches this exhibition as it was a crucial element to the discovery of the DNA structure. The photo was taken by Rosalind Franklin in 1952, a researcher at Kings College who was trying to explore the structure of the DNA through a special photographic technique called x-ray crystallography (Carr 2019).

Crick and Watson, two scientists with the same goal of exploring the DNA structure, used evidence of the helix structure (seen in the picture above) from Rosalind Franklin. They also used other theoretical and experimental results from other researchers to identify the accepted molecular DNA structure in February 1953. Neither researchers conducted their own experiments when they first published their results in the nature magazine (Kahn Academy n.d.).They had even got access the photographic evidence on the DNA structure without the consent of Rosalind Franklin.

One way in which the object contributes to this exhibition is that this photo represents a substantial part of the historical development of knowledge of DNA at the time. Crick and Watson used this (Carr 2019) knowledge to conclude on the final molecular DNA structure (Kahn Academy n.d.).

This is interesting from a TOK perspective as the new knowledge about the DNA structure concluded by Crick and Watson was deducted from past knowledge, from which Rosalind Franklin’s photo of the DNA helix was the most important.

Furthermore, the photographic evidence of the DNA structure from Rosalind Franklin built on historical knowledge of x-ray diffraction methodologies. These were first introduced in 1912 by Max von Laue, a German Nobel prize winner in physics (Thomas 2012). Franklin applied this knowledge to the relevant knowledge area of the structure of DNA from 1950 onwards. This shows that even her discovery, most represented by this shown object, was based on experimental principles of past knowledge in physics.

Generally, it can be argued that the natural sciences create new current knowledge by building on past knowledge. The new knowledge adds to the scientific results accumulated throughout its historical development. In this respect one can argue that the knowledge base in science increases over time.

Object 2: Collection of the German Dictionary Duden


This object is a photo of the multiple versions of the most used dictionary, Duden, for German language. I used the dictionary when I was learning German to correct my grammar. The Duden dictionaries show all German words that are used, their correct spellings and meanings. The Duden stores all knowledge about the currently accepted and official language. The object contributes to the exhibition as this knowledge about language shows a particular historical pattern: words are added (e.g., 3000 words were added between 2017 and 2020 (Heine 2017)) and others are removed.

An example of a word removal was the Nazi word “Volksverräter” (meaning “traitor of the nation”), which was introduced in 1941. It was a term used under the ruling of Hitler and was used for sentencing people to death if they were critical of the national socialism. After the war it was instantly removed from the 14th edition of the GDR Duden in 1951, while it remained in the Duden of the FRG until 1967. The new word formed and abolished reflects events (Heine 2017).

Furthermore, new words such as “Covid-19” and the English phrase “Social distancing” (Heine 2017) were introduced into the Duden during the coronavirus, reflecting the serious threat to the society, the challenges and methods used to prevent further spread of the virus during the pandemic.

Overall, words are removed and added to the Duden dictionary over time reflecting social and political changes that in turn affect language. Knowledge about the German language is reflected in the Duden, but not all knowledge from the past will stay. This contrasts natural science, where knowledge builds on historical results as indicated with the x-ray diffraction picture. It seems that the knowledge, as reflected in the Duden, on language does not accumulate over time.

Object 3: Dowsing rod


This object is a photo of a dowsing rod. It is a historical tool that was introduced during the 16th century and has been used as a tool to find the location of underground water pipes (Britannica, The Editors of Encyclopaedia 2017). This object is relevant to this exhibition as it is still used in water companies today referring to old knowledge about how to handle the rod, although there is no modern scientific evidence that supports the drowsing rod method (Weaver 2017).

Dowsing is an activity whereby someone holds a stick or rod and walking around a site to wait until the rod dips, where water or metals are assumed to be found underground. This is a method of finding water pipes or metals underground, that was applied since the 16th century (Britannica, The Editors of Encyclopaedia 2017).

Although, there is no clear scientific evidence for why dowsing works (Regal 2009), it looks the method has a consistent success rate when identifying underground water reserves (Betz 1995) and is used by farmers and water engineers.

The object is TOK relevant as the handling of a dowsing rod is old knowledge, but the knowledge around the handling never changed nor was it substantiated scientifically. Dowsing has remained as a pseudo-scientific discipline with surprising success rate. In this respect the object suggests that in pseudo- science there is no historical development of knowledge: old “knowledge” is similar the current “knowledge”, in contrast to the knowledge dynamics explained in relation to object 1 and 2.

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