...Einstein said that the experience of the Now means something special for man, something essentially different from the past and the future, but that this important difference does not and cannot occur within physics. That this experience cannot be grasped by science seemed to him a matter of painful but inevitable resignation.
...Any person’s Now is a special event for that person as it is happening. My Now is distinguished from other events I have experienced by being the actual current state of affairs. I can distinguish it from earlier events (former Nows) that I merely remember and from later events that I can only imagine. My remembered past terminates in my Now. The status of any particular event as my Now is fleeting, since it fades into a memory with the emergence of subsequent Nows.
Such a Now is absent from the conventional physical description of spacetime. In physics, all the events experienced by a person constitute a time-like curve in spacetime, and there is nothing about any point that gives it a special status as Now. My experience of the Now suggests that my world line ought to terminate in something like a glowing point, signifying my Now. That glow should move in the direction of increasing time, as my world line grows to accommodate more of my experience. There is nothing like this in the conventional physical description of my spacetime trajectory.
The problem of the Now is solved by identifying the mistake that leads us to conclude, against all our experience, that there is no place for the Now in our existing physical description of the world. There are actually two mistakes. The first lies in a deeply ingrained refusal to acknowledge that whenever I use science, it has a subject (me) as well as an object (my external world). It is the well-established habit of each of us to leave ourself—the subject—completely out of the story told by physics.
The second mistake is the promotion of spacetime from a four-dimensional diagram that we each find extremely useful into what Bohr calls a “real essence.” My diagram, drawn in any fixed inertial frame, enables me to represent events from my past experience, together with my possible conjectures, deductions, or expectations for events that are not in my past or that escaped my direct attention. By identifying my diagram with an objective reality, I fool myself into regarding the diagram as a four-dimensional arena in which my life is lived. The events we experience are complex, extended entities, and the clocks we use to locate our experiences in time are macroscopic devices. To represent our actual experiences as a collection of mathematical points in a continuous spacetime is a brilliant strategic simplification, but we ought not to confuse a cartoon that concisely attempts to represent our experience with the experience itself.
If I take my Now as the reality it clearly is, and if I recognize that spacetime is an abstract diagram that I use to represent my experience, then the problem of the Now disappears. At any moment I can plot my past experience in my diagram as a continuous time-like curve that terminates in the Now. As my Now recedes into memory it ceases to be the real state of affairs and is replaced in my expanding diagram by subsequent Nows. http://scitation.aip.org/content/aip/magazine/physicstoday/article/67/3/10.1063/PT.3.2290
При таком взгляде прошлое отличается от настоящего лишь тем, что я помню его хуже, в меньшем числе деталей, чем настоящее; зато я могу ретроспективно обобщить это прошлое куда лучше, чем наплывающее на меня настоящее.
Вероятно, это следствие конечности памяти, где невозможно хранить всю киноленту. Стирание и компенсирующее его обобщение необходимы; вместе они создают иллюзию прошлого, кардинально отличного от настоящего. Сам процесс компактификации создает "прошлое", которое мы не умеем и не желаем хранить в первозданности.
Для того, чья память совершенна и безгранична, разницы нет.