In this short entry, I will try to list of the Axioms or fundamental principles that we should follow in order to investigate the scientific laws in Equestria. 

Most of the science we encounter have two main branches, Theoretical and Experimental (there is also computational but not sure how we can investigate that in Equestria given computers doesn't really exist there...) . 

Since we cant really carry out experiments (as we do not live in Equestria), we can only investigate evidences that are presented in MLP episodes. And our job is try to explain these phenomenons and formulate a complete picture of science in Equestria. 

Axioms:

Axiom 1:  Anything in the Equestria universe displayed in an episode / movie are considered to be Facts. 

Note on Axiom 1: We should not assume all scientific theorems that works in Equestria universe works in Equestria Girls universe. But this does not mean they don't overlap at all given that they can travel from one universe to the other. 

Axiom 2: Scientific theorems and laws that are true in our universe is also true in Equestria universe. 

Note on Axiom 2: For example, we can assume Newton's laws of motion to be true in Equestria universe as well. Although there can be scientific laws in Equestria that are absent in our universe. So to be more exact, the laws of nature in our universe forms a subset of the laws of nature in the Equestria universe. 

This is the least number of axioms I could think of in order for us to proceed. Hopefully we won't need more in the future but we shall see  . 

Next entry: Lets test things out