Why is Psychology a science?
Psychologists apply the scientific method.
Psychology is branch from philoshopy, philoshopy is science then Psychology is science too
Good & debatable question!!! A number of factors can be considered here. Science is all about fundamentals and it because of its granularity, it provides more facts and no assumptions. Science acts as a catalyst to almost all the studies, "except" understanding of human thought process, which is intangible, complex and yet easily available. That's where Psychology comes in place. Psychology (according to me) is a study of knowledge-process-flow; right from the birth of an idea --> creation of concepts --> dependencies among them --> creation of patterns/behaviors --> finally building knowledge. If you note the flow above, it's clear that psychology is about understanding the fundamental units of knowledge. And hence, Psychology is a Science. I hope it's clear.
Isn't philosophy also the study of fundamental units of knowledge?
Yes. It is. Philosophy is one of the units. It concentrates more on providing facts from the past or can also be a mythical one.
I enjoy refering to the XKCD comic #435:
Join our real-time social learning platform and learn together with your friends!