Answer:
Probably the reasons for different branches of science could be summed up under “ideology”, “methodology”, “principle”, and “tradition.”
Each field of endeavor has its traditional origins and background. For example, metallurgy is a very refined science using electron microscopes, polarized light microscopes, rare earth metals, etc. But, in its background you see a blacksmith hammering iron in his smithy.
The origin of chemistry was alchemy, but what we do in a lab now is a far cry from the image of an alchemist in a dark cellar doing hocus pocus with incantations on the walls. Yet the principles are very much the same as for metallurgy.
Medicine used to be associated with charnel houses, digging up graves under cover of darkness, horrible stenches to be sure. A doctor had low social prestige and a surgeon, even lower. Yet now, among students, the cat’s meow is to become a neurosurgeon.
Geology experienced a revolution with the discovery of continental drift. Going out in the field was a day trip. You remember the sandwiches, the cold shivery arms and legs, sledge hammer and ice pick. It’s hard to get the big picture out in an Ohio cornfield. But now geology is being done from space.
Astronomy is an interdisciplinary field, now more than ever. Do you like it out in the dark under crystal clear skies, with dew on the grass and the chill air seeping through your clothes? Now a powerful rocket blasts off to the heavens, and after nine months starts sending back sharp photos of one of Saturn’s moons.
Geology, chemistry, mathematics, astronomy, and even medicine all become involved in space travel. So we see that, as the various fields perfect their theory, technology, instrumentation, instrumentation, and precision, becoming more normalized and modernized, they also tend to unite together.
In a sense the idea of a “unified field theory” is a sort of a pun, or a play on words — because “field” refers not only to a field of study or a craft — it also refers to the physical force interactions. As the fields unify their knowledge, they also find common grounds and share techniques and mathematical tools. So now we see the present state-of-the-art
