To the commentary on the "now", let me underline a classical distinction. As pointed out by Henri Bergson human time in general, and the "now" in particular are not defined in terms of the physical clock, but rather in terms of events. For instance, when I say "Now, I am writing" many referents may be noted, depending on the context and situation. The sentence may refer to the moment of the writing of the previous sentence itself, to the writing of this paragraph, to the writing of this entire message ("now" not yet completed). In general, the more meaning I can associate with an event, the larger is the scope of my psychological moment, hence of my "now". When preparing a lecture I can say that is all "in my head", when I know a story I have an understanding of it "now". The subsequent delivery of the lecture, or the recounting of the entire story, may, of course, require much time - but cognitively it is one unit of "now". As a rule, the more understanding we have of things, the larger are the chunks of our meaningful unit, and at the same time, the larger is the scope of our "now". Mozart, for instance, was said to be able to grasp an entire symphony in one instance.
Similar observation regarding psychological time, the "now" and its characterization in terms of events are to be found in Wittgenstein's "Remarks on the philosophy opf psychology" and in JJ Gibson's "The senses considered as a perceptual system" (1966). For further discussion see my "The representational and presentation" (1973).