I'd bet a lot of this behavior is heavily correlated with how we generally read top to bottom, which is in itself, probably an arbitrary decision made by ancient text writers.
Writing top to bottom, and even left to right has/had advantages for mostly right-handed writers to avoid moving your hand over and smudging previously written text.
Writing top-to-bottom has advantages for all writers whose eyes are above their hands. The bit of the writing surface that's blocked by your hand hasn't been written on yet.
Extending that, heads have a much easier time moving left and right than up and down, since the motion uses the pivot joints. So, that means rastering left to right, then top to bottom, is the best match to the average reading and writing human (since right handedness is the dominant genetic trait [1]).
Top to bottom advantages everyone. Left to right advantages the right-handed. Right handed being the majority, top to bottom and left to right wins in almost every writing system.
For one, starting at the top and ending at the bottom is natural progress of things because of gravity.
I’m not sure if that means anything, but down-to-up seems very unnatural (of coure I can’t ignore my cultural biases). Is there any writing systems like that?
Gravity is just a random natural process to pick for your point. You could just as easily say “bottom to top is natural because that’s the direction trees grow”.
I don't think "natural" is used metaphorically. If you had an accurate simulation of the human hand you could show that one of the directions minimizes energy usage and damage to your hand, and I think it's the one we use. Starting high means gravity is helping you move down the page, and it's also easier to move your hand towards you than away from you, and the many small movements (rather than the one big one to the top of the next page) are where more energy is spent because of friction.
Writing is done by people and people are almost always subject to gravity. It's one of the 4 fundamental forces. Energy minimization is not an arbitrary selection criteria, it's central to the fitness/design of all living things.
I can agree moving down the page is probably more common due to human mechanics, AND say that trying to make the argument the way they did wasn’t particularly sensible.
I don't think it takes knowledge of gravity/energy/entropy to generalize that things more naturally "fall down" rather things naturally "rise up". But, it's probably a stretch to say that influenced writing direction.
Others have made a possibly more relevant point - in one direction, your arm/hand will block what you have already written.
More languages read right to left than left to right despite most people being right handed, so the blocking what you’ve written thing doesn’t seem to add up either.
I agree human mechanics is likely the reason people tend to write down rather than up though. But I’d say it’s more about our muscles, we’re stronger pulling our arms in than pushing them out. But I’m no expert so would never claim confidence in my assumption there.
yes and we daily see plants growing upward rapidly like 9.8 m/s²... maybe vapour and smoke going up are which we experience collectively as upward going things, but those are quite rare compared to like everything which falls to the ground.
People latch hardest onto a random explanation when they have the least idea what’s going on. The more someone knows, the more complicated and “it depends” their answer will be I’ve found.
A green flag for me that someone might be an expert is when their attitude towards answering a questions has that “it depends” energy.
