Recapitulation theoryRecapitulation is a hypothesis that in developing from embryo to adult, animals go through stages resembling or representing successive stages in the evolution of their remote ancestorsWhy did people believe this theory?The theory originated in 1790, among German natural philosophers. Since the theory was made in a time where there was not much knowledge about growth of babies, and this was one of the only theories about it at the time. This lead everyone to believe in it as they had no knowledge and that there were no other theories to oppose it.Why do people no longer believe in these theories?People no longer believe in this theory, because of the advance in science which has lead to us having better knowledge of how babies develop inside the female. Equipment such as ultra sound, which allows us to see the baby before it has been born in its different stages of growth. Due to this knowledge it is clear that the babies do not go through stages that represent the different parts of their ancestry evolution.Is this theory now obsolete?Yes this theory in now obsolete, as technology has shown us this.
However it is possible that dispute over this theory lead to further research of this topic, and eventually led to our knowledge of growth of babies that we accept.
Caloric theory:Caloric theory:Why did people believe this theory?People believed this because there was no other scientific evidence-
at the time to contradict the theory because no one had discovered-
or proven another theory. Why do people no longer believe this theory?People no longer believe this theory as another theory has been created with more evidence than the last theory and a more believable theory that people can test for themselves. Is this theory now obsolete?This theory is not obsolete in the fact that it describes the movement of heat in substances and that heat can travel. But the theory of fluid in heat is wrong and has been proven so. Also the description of how heat travels has not been described correctly as it has been proven wrong. So aspects of this theory have been proven wrong but some aspects have been proven correct so without these wrong theorys the correct one will take much longer to be found.
Phlogiston Theory:
Phlogiston theory: The theory states that all flammable materials contain the substance phlogiston a substance without colour, odour, taste or mass. Once burned the material will be in its true form calx when not in it's true form it is described as dephlogisticated.When air had become completely phlogisticated it would no longer serve to support combustion of any material, nor would a metal heated in it yield a calx; nor could phlogisticated air support life, for the role of air in respiration was to remove the phlogiston from the body.
Why did people believe this theory?
This theory was stated in 1667 and at that time people had little knowledge-
about combustion so they believed it without hesitation as they had nothing-
to compare it to.
Who do people no longer believe in this theory?
People no longer believe these theories as a better one with evidence that can be tested by anyone and is more believable when rationally thought about.
Is this theory now obsolete?
This theory is now obsolete as all aspects of this theory has been proven wrong and we can sort of tell that this guy Johann Joachim Becher was sort of unsure about the theory and has used aspects of his theory to make it harder to prove wrong for example the characteristics of phlogiston makes it impossible to test scientifically if it is each and every substance that is combustible. But over time a new theory has been created that proves this theory wrong as phlogiston was described in a way basically the opposite of the real role of oxygen and by having evidence to back up the theory as this theory has none. Antoine Lavoisier in 1770's believe that there is a substance called caloric which is the make up of heat. The fluid flows from hotter to colder substances. For example a cup of tea lets out caloric fluid out into the cooler room, therefore raises room temperature and looses its heat.
