The ontology of time in the external world is real , in the same sense that space is real and made of quarks and stuff ie its a Scientific Ideology. External World Time is scientifically defined as the rate of information travel from one point in space to another ie time = distance / speed. In more deeper sense, Time is the rate of causality.
At the same time (no pun intended), in our internal world, the thing that we call time and that which we can perceive and we can feel the passage of, is completely fictional (genetic ideology) and has no relation to scientific time that has to do with information travel and points in space.
What we need to do is understand the difference between the external (scientific ideology) and the internal (genetic ideology) world.
In the real world, there is space which is a quantum graph where random events exist in different states separated by distance. Then there is the internal world, which is conjured up by this information processing system that uses prediction to optimize it’s response to external events. And it’s distinction between present events that have happened and future ones that it predicts will happen is felt by our consciousness (top layer of the information processing neural network capable of inspecting the processing of other layers) as the passage of time…
If the prediction is super fast, like in times of extreme stress, the passage of time is more vivid and so time feels like it’s slowed down. On the other hand, if the prediction is non conscious, like when doing a repetitive task that does not require conscious focus and constant prediction and decision making, like sleeping or sometimes even mundane tasks like driving/cooking, time seems to fly by….
Now lets talk about External World ie Scientific definition of Time that is defined in terms of information travel across distance. Distances in space are real and speed of light aka speed of causality (1 light second ie 3*10^8 m/s) is the upper limit of information propagation across space. Hence, if an alien is moving away from you in space, he’s also moving away from you in time coz now the information that you send him (say the information of your wedding, carried by the photons you reflect while getting married) will now reach him later (say by 100 yrs) than it would have, in case he was standing still at a constant distance from you. Also, the information reaching him (via photons) from earth right now is actually the information that is 100 yrs old from the perspective of people on earth, so he’ll just find out there there is WW1 going on in Earth and that’ll be his NOW. Moreover if the same alien is instead moving towards us, then the opposite happens ie he sees events NOW (ie in his present) that the person on earth will not do for the next 100 yrs. Hence, the PAST PRESENT AND FUTURE ALL EXIST SIMULTANEOUSLY.
So, we see billions year old snapshot of the sky (coz light takes billions of light years to reach us from the distant stars) AND a star in the sky sees a billion year old snapshot (called time slice) of the sun (the sunlight reflected by earth will be too weak to travel millions of years).
The only remaining question is if future exists already, is everything predestined or can we change events of the future by conscious choice aka free will?
If the universe is Deterministic, then we can investigating the brain as a information processing system where all thoughts and decisions even those of the upper levels of the neural net (consciousness) are deterministic and so there is no free will (Meaning that the free will that we perceive is actually deterministic too just like all our thoughts and actions. Note that determinism doesn’t mean there’s a man in the sky that has written your destiny, but instead means that the laws of the universe allow are absolute and hence given the previous state, the next state of the universe can be calculated (by a conscious mind aware of these universal laws) and given that the future already exists, all the next states of the universe exist simultaneously.
On the other hand, if the universe is NonDeterministic ie Random due to randomness at the quantum level (quantum uncertainity, fluctuations etc.) and hence runs on probability (ie if God plays dice with the universe) then, clearly a future state cannot exist at the same time as a past state coz there are infinite futures possible from every past state due to quantum randomness. In that case, the only way to reconcile this is to conclude that all possible futures of every present state exist simultaneously. It still doesn’t give us free will, but atleast we can find solace in the fact that there are infinite copies of ourselves at every instant experiencing everything all at the same time.
Hence, we ie the conscious brain is simply a witness to few (due to our limited conscious lifespan) preexisting events in spaceTime (distribution of events in 3d space is called spaceTime).
The reason we cannot witness our future is coz we ie our conscious brain ie our existance ie all the neurons firing in our brain at this instant in space which includes the neurons that constitute our conscious experience is a part of the overall state of the universe that this instant. In the next instance, the laws of the universe will change the state of the universe either deterministically or undeterministically then the new state of our neurons and hence consciousness will allow us to experience this new state as the present and this will go on and on until there will be a state of the universe where our brain will not exist (death) and so we’ll not exist anymore and so our consciousness will not be able to experience that state of the universe. AND YES, THESE FUTURE STATES DO EXIST SIMULTANEOUSLY WITH THE PAST AND PRESENT STATE IN SPACETIME, but our consciousness exists in only a few states of the universe and so it follows that we can be conscious of only the state we’re in coz that’s the state that our consciousness exists in.
We can still be conscious of the future states of the universe WITH RESPECT TO I.E. RELATIVE TO the present state by MOVING coz Scientific Definition of time is Information Propogation across distance. Hence our current conscious state can be conscious of a past of future state of the universe if it literally travels to that other state of the universe (ie take a conscious chunk of quantum graph namely my brain from one state to another faster than the laws of universe allow ie faster than speed of cuasality), and that’s Time Travel for you. This can be done by travelling faster than information propagation speed or wormholes (moving from one point in space to another faraway point via a shortcut that leverages the shape of spaceTime etc.
In closing, our consciosness is not moving from one state of the universe to another over time. All the states of the universe coexist simultaneously and all that’s happening is that a chunk of conscious quantum graph namely my brain, in one particular state of the universe is perceiving other chunks of the quantum graph in the same state. Also simultaneously the the same chunk of conscious quantum graph namely my brain in the next state of the universe (note that states of the universe are ordered due to cause and effect meaning that the laws of the universe cause the universe to change state causing the 3rd state to be derived from 2nd state and so on. Note that states are just our way of visualizing changes in the universe and states are not real things) is perceiving other chunks of the quantum graph in that same state. And because this chunk of quantum graph has memory ie a way to record information state information, it’s able to link the changes observed in the a part of the external world (another chunk of quantum graph) from one state to another and hence infer the laws of the universe by observing patterns in how one state transforms to another and more importantly, create an illusion of time in our consciousness.