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November 18 Experience and Experiment

Page history last edited by lindsey 15 years, 5 months ago



The 17th century saw a transformation from Aristotelian natural philosophy to mechanical philosophy.  Originally, science focused on the Aristotelian view that science should explain why things in the natural world are true.  They relied on previous experiences to explain current natural phenomena.  The beginning of the scientific revolution soon disowned the Aristotelian way of thinking.  This transformation entailed change in both epistemology and cosmology. Mechanical philosophy highlighted the use of contact action and the disregard for occult properities. In addition, the rising mechanistic philosophers emphasized the newness of their own ideas and approaches.   

 One new method was explicitly experimental, favoring craft and practice and trial and error over strict observation. One instance of such reasoning was Galileo's Hypothetico-Deductive Method, in which prediction was made rationally but tested experimentally. Much more focus was put on empirical experimentation and the use of tools to discern the nature of the universe.  The new philosophy held that one must actually do hands-on experiments, merging the craft/artisan trades and science.  Also, a new emphasis was laid on practical discovery and the development of technologies as attitudes shifted toward the idea that the purpose of science was to control nature and benefit mankind. Many new instruments, such as the telescope, microscope, barometer, and air pump, were either invented or improved in this time period as a result of the focus on the practicality of science. 

However, the experimentalists faced several problems.  The first was establishing trust in experimentation with academia and the public.  Even though practical philosophers were growing in numbers, they still initially came under the scrutiny of an established epistemological order contrary to experimentation.  The second difficulty was in extending universality from experiments conducted in artificial settings.  Why accept a result as true in every situation when special conditions had to be created or manipulated just to reach that conclusion? 

The image of "twisting the lion's tail" demonstrated (in an exagerrated way) the epistemological difference between Aristotelian natural philosophers and the mechanical natural philosophers. Where an Aristotelian would come to knowledge about lions via unintrusive observation from a distance for lengthy periods of time, a mechanistic philosopher would argue that in order to really understand lions, one must walk up to one and yank its tail.  


Evangelista Toricelli (1608-1647)

Known for his work with the barometer, Toricelli discovered that when a tube closed on one end is filled with a liquid and placed open-ended in a bowl of the same liquid, a small open space remains at the top of the tube. Curious as to what caused the open space, Toricelli performed the same experiment with mercury instead of water.  No matter the volume, shape, or angle of the tube, the column of mercury consistantly remained at around 29 inches. He later concluded that the reason mercury did this was because of the weight or pressure of the air.



Blaise Pascal (1623-1662)

            Pascal was a French philosopher who experimented with mercury-filled tubes similar to Torricelli. He hypothesized that altitude would affect the height of mercury in the tube, and had his brother climb a mountain, recording the height of the mercury at different altitudes. What resulted was a direct correlation between the height of the mercury and the altitude. The higher the altitude, the lower the mercury, showing that the height of the mercury was affected by the pressure of the air.


Otto von Geurike (1602-1686)

The vaccum pump was invented by Otto von Geurike who took two hollow hemispheres and removed air from them with a vacuum pump.  The pieces stuck together and would not come apart, but if the smallest amount of air was let into the hemispheres they detatch easily. Without this air in the sphere, the hemispheres are impossible to separate. In fact, teams of horses were connected to each side of the sphere, and even they could not separate it. To this day, this experiment is celebrated in and around the area where it was conducted, and it is not uncommon to find representations of the Geurike hemispheres displayed.


Francis Bacon

Another philosopher at the time was Francis Bacon who wrote the work, The New Organon (Novum Organum), which was a play on the title of Aristotle's book of logic (the Organum). The book, written in a series of aphorisms, described Bacon’s attempt at a new method for understanding nature. One of the major areas that Bacon attacked in Aristotelian logic was the syllogism. The syllogism is deductive, and as such generates knowledge of particular instances from global claims. By this method, Bacon argued, no new knowledge was actually generated. Bacon believed that only through induction, making general claims from particular instances, could one acquire new knowledge. Bacon desired to gain all the knowledge of nature possible in order to control it. He believed that man had a right over nature which was God's gift. He was also a believer in practicality, and thought the old methods of natural philosophy did nothing to better mankind, and were thus worthless. 


Robert Boyle

One philosopher in particular that studied Geuricke’s experiment was Robert Boyle who tried to figure out why the spheres acted the way they did.  He hired Robert Hooke to improve on the device. This new device was called a pneumatical engine. From this, Boyle wrote the book, New experiment physic-mechanical touching the spring of the air and its effects, which said that there was a space above the mercury not because of a finiculus, an invisible string, as so believed, but because air had a spring, discovered through his experimentation with the J tube.  


Isaac Newton

            Another important philosopher at the time was Issac Newton (1642-1727) who had a new theory about light and colors. Newton described white light as complex, containing all of the colors mixed together.  In his work, A New Theory of Light and Colors in 1670, he showed by experimenting with prisms the idea that white light is all the colors mixed together. (Before this, many including Descartes thought white light is simple and that colors are modifications). In his "crucial experiment," Newton used two prisms to divide white light into the various colors and then recombine all colors again into white light, effectively demonstrating that prisms do not make colors: they only separate out the colors. 



Primary Sources


Key terms and definitions:

Barometer- An instrument that measures atmospheric pressure.   


Syllogism- Aristotelian form of deductive reasoning in which a conclusion is found  from two premises. 


Finiculus- (Latin: string) invisible string on the top of a column holding mercury up.


Hypothetico-Deductive method- An experimental method utilized by Galileo in which a prediction is made based on mathematical knowledge and then proven through physical experimentation.


J tube- A J-shaped glass tube used by Robert Boyle to show that air had a spring.


Relevant Links_______________________________________________

Comments (6)

liz mastroianni said

at 8:25 pm on Nov 18, 2008

really basic summary of class today, some could be added

Nicole Hagstrom said

at 5:55 am on Nov 19, 2008

I did mostly structure work.

Garrett McCormack said

at 4:15 pm on Nov 19, 2008

I just added some more overall summary.

Grant Berry said

at 9:01 pm on Nov 19, 2008

Added stuff on Bacon and Geurike, and a little bit on Pascal.

jgm829@... said

at 9:41 pm on Nov 19, 2008

I added a little info on Geurike and fixed some grammar.

jonathan stutte said

at 11:29 am on Nov 20, 2008

didn't add much, just a little to the intro paragraph about some objections.

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