Many years ago, when I first contemplated how we could have conscious experience I imagined that the brain was like a computer. Its parts were arranged over a few centimetres of space and at each instant it had a particular state in which some components were active and others quiescent. I then wondered how my experience of time passing could occur.
The first model of time passing that sprang to mind was of my "brain machine" being "washed over" by events in the world. A bit like exposing my brain to a 3D movie. I could imagine that only one frame of the movie existed at any moment.
The second model was a bit like the first but with time existing so that my brain moved through time rather than time moving through my brain.
It didn't take long for me to realise that both of these "models" were theories based on ideas about how the world worked, they were based on cosmology - the way events are arranged in time and space. I didn't like this theorizing because a scientist should observe the world and then theorize, not vice versa. This led to another idea of time in my experience.
If I actually look and listen it is obvious that events can occur simultaneously. Simultaneous events define a "space" so the simultaneity in my experience means that it is spatially arranged. I also notice that I can hear whole words and see things move so my experience extends through time. My conscious experience is an actual set of events arranged in space and time somewhere.
When I consider how events are arranged in the space of my experience it is clear that they have different angular displacements at the centre of that experience. The written word "go" on this page makes a smaller angle at the centre of my experience than the written word "simultaneously". It is also clear that when someone says "go" the word appears at their lips in my experience and is extended in time at their lips. If they say "begin" the word has a bigger angular separation at the centre of my experience (at my "now") than the word "go".
Both spatial and temporal "lengths" in my experience have angular separations at the centre of my experience. The centre being a geometrical point that is both a spatial point and instantaneously "now". So two separate times can be simultaneously present "now" because they project at a single point in the present instant. This seems weird but consider a rod on a table in front of you, both ends are simultaneously present and have an angular projection at a viewing point that cannot easily be found in the physical world. The point is not the point at the centre of my eye (I have two eyes and, if you know about geometrical optics it is clear that there is no simple physical point).
It turns out that this observation about the time within my experience is consistent with modern physics and cosmology. More surprising still, my earlier ideas are not consistent with modern cosmology, they are based on the cosmology that is assumed in school physics and this cosmology is wrong! (See Time and Conscious Experience )