OppThink Example: Lavoisier Proposes Oxygen Theory of Combustion, Opposite of Phlogiston Theory

Here is another example that shows how great moments in history can be sparked by OppThink. From the webpage "Demise of Phlogiston" (http://web.fccj.org/~ethall/phlogist/phlogist.htm):

Antoine Lavoisier (1743-1794) When informed by Priestley about dephlogisticated air, Lavosier repeated the experiments quantitatively. But to make exact measurements Lavoisier developed a balance that could weigh to 0.0005g. From his experiments Lavoisier proposed the Law of Conservation of Mass as well as the oxygen theory of combustion. Phlogiston died on September 5 1775, the day Lavoisier presented a paper to the French Academy of Science. Here are excerpts from the paper, Memoir on Combustion in General, published in 1777:

I venture to propose to the Academy today a new theory of combustion. Materials may not burn except in a very few kinds of air, or rather, combustion may take place in only a single variety of air: that which Mr. Priestley has named dephlogisticated air and which I name here pure air. In all combustion, pure air in which the combustion takes place is destroyed or decomposed and the burning body increases in weight exactly in proportion to the quantity of air destroyed or decomposed.

These different phenomena of the calcination of metals and of combustion are explained in a very nice manner by the hypothesis of Stahl, but it is necessary to suppose with Stahl that the material of fire, of phlogiston, is fixed in metals, in sulfur, and in all bodies which are regarded as combustible. Now if we demand of the partisans of the doctrine of Stahl that they prove the existence of the matter of fire in combustible bodies, they necessarily fall into a vicious circle and are obliged to reply that combustible bodies contain the matter of fire because they burn and that they burn because they contain the matter of fire. Now it is easy to see that in the last analysis this is explaining combustion by combustion.

The existence of the matter of fire, of phlogiston in metals, sulfur, etc., is then actually nothing but a hypothesis, a supposition which, once admitted, explains, it is true, some of the phenomena of calcination and combustion; but if I am able to show that these phenomena may be explained in just as natural a manner by an opposing hypothesis, that is to say without supposing that the matter of fire or phlogiston exists in combustible materials, the system of Stahl will be found to be shaken to its foundations.

Pure air, the dephlogisticated air of Mr. Priestley, is then, from this point of view, the true combustible body and perhaps the only one in nature, and we see that there is no longer need, in explaining the phenomena of combustion, of supposing that there exists an immense quantity of fixed fire in all bodies which we call combustible, that on the contrary it is very probable that little of this fire exists in metals, sulfur, and phosphorus and in the majority of very solid, heavy, and compact bodies; and perhaps even that only the matter of free fire exists in these substances by virtue of the property which this matter has of coming into equilibrium with neighboring bodies.

Furthermore, I repeat, in attacking here Stahl's doctrine my object is not to substitute a rigorously demonstrated theory but solely a hypothesis which appears to me more probable, more conformable to the laws of nature, and which appears to me to contain fewer forced explanations and fewer contradictions.


This last paragraph is key. When an OppBelief (such as Lavoisier's "opposing hypothesis") seems "to contain fewer forced explanations and fewer contradictions," you are on the right track, and that OppBelief has a good chance of becoming accepted. Lavoisier's Oxygen Theory -- which sprang from his "opposing hypothesis" that a substance does not burn due to containing phlogiston but rather because the air around it contains oxygen -- explained existing data in a better way, and eventually supplanted Phlogiston Theory.

Another example from science: Copernicus, whose controversial hypothesis that the Earth orbited the Sun (rather than the other way around) also entailed fewer exceptions, forced explanations and assumptions, and reduced contradictions.