In the 18th and 19th centuries, natural philosophers were making great claims on the nature of the world around them. Although they did not have some of the technology that is available today, they were able to make assumptions about the composition of certain substances through the inference of data from their experiments. One of the main subjects of debate was the substance called phlogiston. Some natural philosophers thought of phlogiston as a substance, such as earth, and others thought of it as an explanation for the combustion of certain materials. The two natural philosophers that had dissenting views on the nature of phlogiston were Antoine Lavoisier and Joseph Priestley.
[...] Wallace compares the structures of a human body to those of apes, and finds that find that, in a variety of characters, all these apes resemble each other and differ from man, so that we may fairly say that, while they have diverged somewhat from each other, they have diverged much more widely from ourselves” (Darwinism, 453). He argues that although man has many similar features, the unusual qualities separates man from apes. This caused Wallace to believe that although man and apes may have had an initial common ancestor, man must “have diverged from the common ancestral form before the existing types of anthropoid apes had diverged from each other (Darwinism, 456). [...]
[...] Rather, this compound can only be changed back when exposed to what Priestley calls “inflammable or when mixed with other substances that are thought to contain phlogiston. (Considerations, 24) This “inflammable is known as hydrogen, which was found by Priestley to produce water when exposed to oxygen. Lavoisier based some of his ideas, like the formation of water, off of Priestley and then expanded on them. Lavoisier's work on the decomposition of water and the rusting of iron is strongly debated by Priestley, because he says that the same processes can be described by the phlogiston theory. [...]
[...] His work on the evolution of man was radical and strongly opposed by Wallace, along with other natural philosophers. Many still believed at the time that all species were created by God to fit their needs, although many natural philosophers followed an evolutionist theory for animals. Darwin's suggestion that humans evolved just like every other creature suggested that the bible was incorrect. The definition of species therefore slowly changed in favor of the scientific instead of the religious term. Both scientific revolutions were important, but very different in nature. [...]
[...] that these misconceptions, such as the belief that everything in nature is composed of the four elements earth, wind, fire, water were thought up through philosophy and not gained through the trials of experiments. Lavoisier rejects the idea of phlogiston, because it is more a philosophical idea than scientific. Instead of using the term phlogiston, Lavoisier claims that there is a force called Attraction, which keeps the particles of a substance together although they do not touch. He has found in his experiments that when a substance is heated, it tends to expand, and when it is cooled again to its initial temperature it returns to its initial size. [...]
[...] The second revolution that occurred in the 19th century was due to Darwin's works on the evolution of species and natural selection. Natural selection suggests that throughout time interminable number of intermediate forms must have existed, linking together all the species in each group by gradations as fine as our present varieties” (Origin, 462). This shows that evolution took place over a long period of time and had many different outcomes. However, all the outcomes are not seen today because some of the species have died off, leaving only the species seen in present time. [...]
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