I was doing research on EVM and solidity and I came across this fact that the calldata/input data is created using RLP encoding and stuff. I know the process and I don't want to elaborate on that. My question is, what is the logic or maths behind choosing the first 4 bytes of data for identifying the method? Why not 5? Why not some other number?
For example if the call data is:
Then why do we take only the first 4 bytes, i.e.,
ee919d50 as the method id and not more or fewer bytes?
I also read from the first answer to this question: How does the EVM find the entry of a called function? that said that if you want to implement your own logic, you can consider the first 8 bytes of data instead of first four bytes. I am interested in knowing the actual reason for selecting the number "4".
I would appreciate if someone could explain or point a resource that has a detailed explanation of this question.