The point is that when we learn about scientific theories and ideas...

The point is that when we learn about scientific theories and ideas, we must look deeply into what has been said, and be careful to examine them with specialists in each matter so that the truth may become clear. Because it is possible that inattention to these matters may result in a weakening of our beliefs. Moreover, we must not submit to a theory without carefully examining it, so that we imagine it to be an indubitably ascertained fact.

There have been many theories, which have been supported through the ages by various scholars, but which were refuted later and all traces effaced. An example of this is the theory of phlogiston whose history we have just related. Even the theory of Lavoisier has lost its original form (the principle of the conservation of matter), and has become the principle of the conservation of matter and energy.

For example, if 8 grams of oxygen were made to react with I gram of hydrogen, Lavoisier's theory would predict that 9 grams of water would be formed. But we now understand, through more exact calculations that a small part of the substance is converted into energy and that the amount of water formed is a little less than 9 grams. Questions What substance forms the flame in a burning fire? What was people’s opinion about this phenomenon before the opinion of Lavoisier?

Whose theory says, “Nothing perishes and nothing is created?” What should be our attitude to the changing theories? Should we accept some opinion without ascertaining its truth? Is it true that flame is a certain form of substance that comes out of the burning materials? Does Lavoisier’s theory deal with whether the world is created or not? What happens to the gases coming out of the burning materials and the oxygen present around?

Is there a difference between a philosophical and a chemical issue? Is Lavoisiers’s theory a chemical or a philosophical issue? Does the principle of the conservation of matter prove that it is not created? What change has taken place in the theory of conservation of matter? Previous…