For that we invent a way to measure that mass.
And for that there are many different ways. One way links to inertia, where you measure how much force is required to accelerate it.
The other is based upon weight, where if you know the value of g, or you have a comparison and can account for buoyancy, then you can measure it.
The fact that we can measure it doesn't magically mean it is made up.
Mass and weight are real and exist independent of measurement.
You measure the water displacement.
Which only works if the ship floats, as it is displacing its mass in water.
If it takes effort to pick up an object them that same effort will be required to hold the object, meaning you are holding an object that displacing the atmosphere it takes up at any point.
That atmosphere is acting back onto the object and is trying to compress it back to the foundation but you've become that foundation for as long as you hold it.
And that would mean if I am holding it from above, which can happen transiently such as when you are bouncing a basketball, the atmosphere should be pushing it into my hand and I should need to force it down. But the atmosphere is also pushing my hand down, which cancels is out meaning no force and I should just be able to hold it up.
If I let it go so it is in the air, then the air is pushing all around and it should just stay floating.
No floating as you say.
You are yet to provide a reason why it shouldn't float.
The atmosphere is stacked. There is more atmosphere above you and around you than below you.
So? That is merely a result of being near the bottom of the atmosphere. It doesn't magically mean it pushes me down.
Any energy pushing into that atmosphere will compress it, whether it's expanded matter or dense objects.
Again, that requires the matter to pop into existence from no where.
If it already exists, it is already pushing into the atmosphere. Moving it around isn't magically pushing into more atmosphere, it is just pushing into different atmosphere, and the pressure of the atmosphere pushes back, in all directions.
will crush it
Yes, and that crushing is in all directions. Again, a plastic bottle is a good example of that. If it is a lower pressure inside it can easily be crushed by the atmosphere pushing in and it does so in all directions, not just downwards.
So again, this does not provide a reason for a downwards force, and thus if you let go of an object it should just stay floating. If you jump, you should float.
just like the water will crush back against the ship and you get your buoyancy you're looking for.
Again, we have been over this. That is because there is a greater pressure the lower you are, something you are yet to account for/explain why it happens, and this ALWAYS result in an upwards force, even in air. It NEVER results in a downwards force.
In order to get a downwards force in the atmosphere the atmosphere would need to be inverted, being a higher pressure the higher you are.
And you would still need to explain that.
Stop just saying pressed and crushed and so on. You have provided absolutely no justification for any directionality other than the upwards force due to buoyancy.
You said things don't just appear from nowhere, so I gave you a tree growing from underground then out of the ground.
And the tree doesn't just magically gain that matter. It is simply moving it. As such, according to you it is displacing the same amount of air.
Or are you going to claim objects don't displace atmosphere underground and thus if you go underground you will be weightless?
There's no magic about it.
Until you provide an actual justification, explaining why things are pushed down, it is magic.
You place any object into that atmosphere
Again, the object is already in the atmosphere.
As such, no extra energy should be required in your model.
Even if it did magically require energy, that still provides no justification for why the object should be pushed down.
I believe I've explained. You refusing to grasp it is not my issue.
You believing something doesn't magically make it true.
You have repeatedly failed to explain why things go down.
Instead you just repeatedly assert the same magic downwards push from nothing.