How do historians set the causal relationships of past events ?

Question

For instance:The causes of the Frech Revolution: the causes of the expansion of christianity in ancient times, etc.,etc.

Answer 1

Our view of how historical events unfold changes ever so slightly with newly discovered evidence and sound theories. A historian tends to specialize in one or two periods of antiquity and they will have a considerable background knowledge in respect to their chosen field. They will also be aware of most of the previous academic writing by other historians who research similar avenues. They also have access to valuable primary source evidence which was created during the period in which they are interested and they have the mental tools with which to dissect it fairly. I've lost count of the number of times on here that I've seen the old chestnut, 'History was written by the winners' and is thus one sided, well maybe so, but a proper Historian is aware of this and can find other evidence to compensate or show up the story of the 'other side'.

In the case of the causes of the French Revolution, historians have read and dissected each others work on this subject, poured over thousands of primary sources and have come to some agreement of the probable causes for the revolution. They make informed and educated statements according to the evidence that they have. Nothing is certain but a lot is probable.
The same is relevent for any other decent theories abound.

Answer 2

I'm not sure about your use of the word "set". The events set themselves in motion, the historians simply document it and argue about which causes correspond to which effects.

Answer 3

by the fossils and study of history in brief