Its easy though:
RE Theory:
1 - Up = outward.
2 - Up = up + outward.
3 - Outward = up.
4 - Outward = outward + up.
Confused? I am.
In RE theory, the words "up" and "outwards" have to mean exactly the same thing for the earth to be a sphere. In RE, anything traveling upwards at 90 degrees to the earths surface is "up" and also it is "outwards" at the same time. "Up" and "outwards" are interchangeable words in RE theory. A quick look in the dictionary shows us that up is not outwards, although I do not claim an English Dictionary to be 100% applicable here, lets use it to see what the words "up" and "outwards" mean as described by an English Dictionary:
Up
1. to, toward, or in a more elevated position: to climb up to the top of a ladder.
2. to or in an erect position: to stand up.
3. out of bed: to get up.
4. above the horizon: The moon came up.
5. to or at any point that is considered higher.
Outward
1. proceeding or directed toward the outside or exterior, or away from a central point: the outward flow of gold; the outward part of a voyage.
2. pertaining to or being what is seen or apparent, as distinguished from the underlying nature, facts, etc.; pertaining to surface qualities only; superficial: outward appearances.
3. belonging or pertaining to external actions or appearances, as opposed to inner feelings, mental states, etc.: an outward show of grief.
4. that lies toward the outside; that is on the outer side; exterior: an outward court.
5. of or pertaining to the outside, outer surface, or exterior: to make repairs on the outward walls of a house.
This shows us straight away that the words "up" and "outwards" mean entirely different things in the English language - but to pass off a spherical Earth, RE'ers must use made up meanings somewhere along the way in order to marry the word "up" with the word "outwards" and claim that standing on earth throwing something up is to also at the same time throw it outwards.
If an RE theorist thinks, that he is throwing a ball "up" towards space, he also thinks he is throwing a ball "outwards" towards space. This cannot work in FE theory, because there can't be "outwards" only "up".
The FE theorist cannot explain this away on behalf of the RE theorist, nor can the FE theorist help the RE theorist out in any way with this error, except to explain as I have here that they are using two different words with 2 different meanings to describe the same thing, which is an impossibility because the dictionary, under "outwards" doesn't mention the word "up" and under the word "up" it does not mention the word "outwards".
I am not "splitting hairs" or "arguing semantics" or "nit-picking" or being "wrong" here.
The RE theorist himself also cannot explain why he uses the two differing words "up" and "outward" interchangeably either.
FE Theory:
1 - Up is up.
2 - Outward is outward.
Up is simply a one directional thing, away from the acceleration that is happening underneath.
Outwards is a scary concept to the FE theorist, it means passing beyond the wall of the cylindrical tube we are going up inside.