"If we have data, let's look at data. If all we have are opinions, let's go with mine."
|--Jim Barksdale, former Netscape CEO|
Data science is a very broad term, and can assume several different meanings according to context, understanding, tools, and so on. There are countless books about this subject, which is not suitable for the faint-hearted.
In order to do proper data science, you need to know mathematics and statistics at the very least. Then, you may want to dig into other subjects such as pattern recognition and machine learning and, of course, there is a plethora of languages and tools you can choose from.
Unless I transform into The Amazing Fabrizio in the next few minutes, I won't be able to talk about everything; ...