Yes. The word Time has two distinct contexts, and in both it references change / change-events:
In both cases Time is abstract. Change/events are the tangible reality.
Einstein actually admitted to not knowing what Time is, but conjectured that it was probably “man-made”….he may have meant abstract.
Interesting how he formed a theory founded on Time (spacetime), when not knowing precisely what Time is.
You try putting forward a theory based on a vague, ill-defined noun, and see how far you get.
And Physics still hasn’t defined or understood Time since. That is a big black hole…
Time clearly is a dimension.
Do you know what dimensions are? They are abstract measurement, calibration and indexing frameworks. They are how we measure, calibrate and index an underlying subject.
Example1:- Temperature is the dimension of heat. Temperature is how we measure, calibrate and index heat. Temperature is abstract; heat is real.
Example 2. Space (a word with multiple meanings) in this context is how we measure, calibrate and index relative position.Hence xyz axis. Space (in this context) is abstract, position is real.
And Time (in this context…time is also a word with multiple meanings) is the dimension of change. Time is how we measure change rate.
For example. A change of position is measured in, say, miles.
The rate of change of position, aka motion, is measured in miles PER HOUR. The ‘per hour’ bit is the dimension known as Time.
Time is hence the dimension of change. Time calibrates change. Time (in this context) is abstract. Change is real.
(Btw..if Space is the dimension of relative position, Time the dimension of change, hence Spacetime is the dimension of changing position aka Motion.)
No.
Thats why its called the future. By definition, it has not already happened.
Prof Hawking also stated on page 1 of Brief History that he didn’t actually know what Time is.
So he’s perhaps not best placed to comment on Time.
What is Time? 