O nosso futuro é tão imutável como o nosso passado, amigos...

Eternalism (philosophy of time)

Eternalism is a philosophical approach to the ontological nature of time, which takes the view that all points in time are equally "real", as opposed to the presentist idea that only the present is real. (...)

This would mean that time is just another dimension, that future events are "already there", and that there is no objective flow of time. It is sometimes referred to as the "block time" or "block universe" theory due to its description of space-time as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time.(...)

Problems with the flow of time

Conventionally, time is divided into three distinct regions; the "past", the "present", and the "future". Using that representational model, the past is generally seen as being immutably fixed, and the future as undefined and nebulous. As time passes, the moment that was once the present becomes part of the past; and part of the future, in turn, becomes the new present. In this way time is said to pass, with a distinct present moment "moving" forward into the future and leaving the past behind. This view of time is given the name presentism by philosophers.

This conventional model presents a number of difficult philosophical problems, and seems difficult to reconcile with currently accepted scientific theories such as the theory of relativity.

Eternalism addresses these various difficulties by considering all points in time to be equally valid frames of reference—or equally "real", if one prefers. It does not do away with the concept of past and future, but instead considers them directions rather than states of being; whether some point in time is in the future or past is entirely dependent on which frame of reference you are using as a basis for observing it.

Since an observer at any given point in time can only remember events that are in the past relative to him, and not events that are in the future relative to him, the subjective illusion of the passage of time is maintained. The asymmetry of remembering past events but not future ones, as well as other irreversible events that progress in only one temporal direction (such as the increase in entropy) gives rise to the arrow of time. In the view suggested by Eternalism, there is no passage of time; the ticking of a clock measures durations between events much as the marks on a measuring tape measures distances between places.

Eternalism has implications for the concept of free will, in that it proposes that future events are as immutably fixed and impossible to change as past events (see determinism). (...)

Mais aqui

X-rays, dark matter and galaxies in cluster Abell 2744