Does time really exist?
The measurement of time by humans is somewhat arbitrary. But the passage of time is not. It's a physical fact.
Often we see some fringe scientific theories expressed as "time does not really exist." These are unfortunately laymen interpretations of theories that they laymen in question didn't understand.
There are no theories in modern science which state that time does not exist. There are theories in modern science which state that the "nature of time" may not be what we think it is in terms of general relativity. But for the most part, every modern scientist in the world understands completely that time is a real and observable thing that operates independent of the existence of humans.
It existed before we arrived in the universe. It does now that we are here. And it will continue to do so long after we are gone.
They have a saying in skeptic realism. Even though it is the method of the skeptic to question all things, whether possible or impossible. If you question too much of reality, eventually your questioning turns into denial, and denial is just another form of delusion.
Facts should only be questions if a realistic and viable challenge to that fact can be produced. Otherwise, you are just engaging in the pursuit of ignorance, not knowledge. Reversing the progress, so to speak.
Being incomplete is not the same as being wrong. Nothing natural is complete in the human experience. But it doesn't logically follow that everything is wrong because it is not complete.
Since humans do not "know" all the processes and programming that leads up to part of the computer that we are capable of knowing, it is not the knowing that makes it work. If it was the knowing that makes it work, one of two things must be true:
1) We know ever single process of the computer as it happens.
2) The parts of the computer we don't know do not really exist and are just projections of our consciousness.
The first option is a form of philosophical monism, which though not entirely impossible, doesn't explain the need to have computers in the first place. We have computers because of a need that evolved to build them.
The second is a form of philosophical idealism. And if you have known me long enough, you have heard me go on and on about how idealism is "psychic friends network" of philosophy. Don't waste your time on it.
The same goes for time itself. The possibility that it is the product of our mind is so far removed from the reality of the science that you might as well be saying time is magic.
Neuroscience has proven that we have a cognitive sense of time that reacts to stimuli outside of ourselves like most of our senses. Just like our minds do not produce the photons we see, our sense of time does not produce temporal order. It is therefore not just our mind tricking us into believing motion is real.
And from a physics point of view, no time, no causality. No causality, no existence. If there is no physical time, then we should not be having this conversation. We should not even be here.