Chemist: Stanislao Cannizzaro (1826 -1910)

12 01 2012

Recently I read a very good paper that all of those trained in chemistry should read IMO. The paper is briefly discussed in Harriman’s book, The Logical Leap

Sketch of a course of chemical philosophy (1858).
I have linked to the PDF version of the article.

Ask a recent chemistry graduate from a university this question: How did scientists prove that matter was made of atoms? How do we really know things are made of atoms?
Tell them that the scientific world basically agreed this was the case in the middle of the 19th century. ie: Long before the invention of our advanced spectroscopy instruments, X-ray diffraction, electron microscopes, nuclear magnetic resonance etc. These instruments would perhaps not have even been developed to their current day levels without atomic theory because there would have probably been less interest in the types of instruments that investigate the behaviour of atoms if people didn’t believe atoms existed.
The human eye sees wavelengths of light as small as about 390 nm. But an atom is over 1000 X smaller than that and obviously cannot be directly perceived with our eyes alone.

When I graduated 9 years ago, I couldn’t have answered this question. Seems like it should be a pretty easy thing to answer doesn’t it? But the way science is taught in Australian schools is a hodge-podge of Constructivist BS which often amounts to nothing more than indoctrination. Students unfortunately don’t learn about how scientists validated atomic theory. I have come across academic pedagogues who dispute the idea that teaching science history necessarily aids in scientific understanding. However a paper like this demonstrates the power of an investigation into the essentials of science history. Because when studying science, the scientific method itself, the method of achieving accurate knowledge of physical reality is far more important than the results themselves. Once you have the method, it can be applied to any area of science. And by investigating the type of work needed, the disagreements that occurred, the errors that were made, students can see for themselves the process of scientific method at work.
They no longer just believe that everything is made of atoms on faith – everyone knows that right? They are encouraged to stop and check this seemingly obvious assumption. They can independently validate the theory for themselves. The process of scientific discovery has been highlighted and they aren’t just required to accept theories from the Oracle of Science. They see what was required to validate atomic theory and can appreciate the brilliance of the great scientists and their intellectual determination and rigor. So without even necessarily focusing on the topic of scientific method, they are nevertheless investigating it and coming to appreciate its importance.

So thank you Cannizzaro! 🙂

Cannizzaro’s paper answers the question. It’s very interesting and has inspired me to go look up some of the original work done by Avagadro, Dumas, Ampere, Dalton and Gerhardt.




2 responses

15 01 2012

it should also be noted that a number of philosophers, historians and sociologists of science (perhaps most notably Paul Feyerabend ) claim that such descriptions of scientific method have little relation to the ways science is actually practiced.

16 01 2012
Tim R

Yes, I think I know what you’re saying Mercadeo but I haven’t read much of Paul Feyerabend.

The issue of how the scientific discovery process itself works is confusing because a scientist brings so much prior knowledge to the table. So there is always a prior theoretical framework (and tons of conceptual knowledge) in the scientist’s mind before he integrates any experimental data. Therefore this leads some to claim that ultimately it’s some kind of conceptual level theorizing process that is fundamental to discovering new scientific knowledge as opposed to a mind that can focus on and interpret the essential attributes of observed, empirical data. Objectivism disagrees by claiming that all knowledge ultimately rests on perceptual data if you dig deep enough. Objectivism is quite different to the philosophy of John Locke but does adopt the “tabula rasa” approach to epistemology (the slate has its own nature, but it is blank. Knowledge is initially added to the slate, validated by perceptual experience and conceptual knowledge is built on top in a hierarchical process).

Not sure if you know or not but when this book came out there was A LOT of debate about it even just in the Objectivist community and of course there was the resignation of John McCaskey.

I really liked the book myself, but in some respects I did not think the book was very in-depth or thorough. I think there’s potential for a lot more work in this area.

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