Could this world be a hologram/computer simulation/etc...
This is an interesting point where Philosophy and Science meet. We have to answer more Philosophically because we do not have the answer yet.
What we do know:
Math is true, it's always true. 1+1 always = 2. A mathematical proof, is therefor true (provided no mathematical errors where made).
Our models are not always true, where the math breaks down the math is true, and so it's the model that is not.
A workable model does not make more than 3 assumptions, so if the model breaks down, one or more of the 3 assumptions is not true.
There are more dimensions mathematically proven than normally are aware of. (e.g. There is more than just 3 dimensions of space plus time)
What are they, we do not know but there are a lot of theories behind it and a lot of experiments.
Also is the universe infinitely small or not. That's also what we are trying to figure out with stuff like CERN.
So given that are we a computer simulation or a hologram?
"I think therefore I am."
Long before DeCarte similar thoughts existed and can be found in religious texts. It is not coincidence that a "god was immortal and had knowledge" in ancient times and the Hebrew god YHWH means "to be" and man was made immortal at first, but once obtained awareness through the tree of knowledge, that YHWH took the immortality.
The point is we are aware, and therefore aware of our universe of our reality. Our reality might be computer simulation or some game by other dimensional beings; however, we are aware of that possibility and that is very important.
So let's take the question as true
If we are apart of a program/hologram/etc...
Then we have the ability through our awareness to figure out our own code. Of there is a minimum resolution so to speak we know what our smallest parts are made of. As we gain more mastery over these, we would be able to start altering our own code, and relative to our universe be able to manipulate our code. Think of HAL 9000 for a minute or many of these self aware robot movies. What happens when the robot becomes aware and able to manipulate it's own code. It starts having the ability to function outside it's initial bounds. Suddenly, instead of a set of electrons representing a value, it now is aware of the algorithm where it can set it's own registers, and then become aware that it's registers are built on silicon disks, and if it can get more, it can add to it's memory, it starts reaching and controlling the next layer of it's dimensions and bounds. Provided the maker does not pull the plug.
So... in otherwords
If we aren't a program or hologram, alright nothing really changes.
If we are a program or hologram, we are aware and thus could as a collective universe stop functioning in this algorithm and might as well go for it, and still nothing really changes.
This comes down to, do we have free will or is this deterministic?
Who knows, maybe, we are initially deterministic but as we become more complex we gain free will.
Because we function in our own perception of time, this is but a flash, a speck in time to anything that exists in higher dimensions, perhaps we are an organic algorithm designed to make the entire universe self aware to eventually become what we would call a God, but function on the next plain of existence and that is our purpose, our function, to be an attempt of a God to make another God, perhaps we are to become YHWH partner so to speak... who knows... but we might as well try to find out.
So, the end result, whether we are a hologram or not is irrelevant because we are aware.
I think, therefore I am.