Tuesday, 21 August 2012

When is now?

When we look at a scene, we are constructing an understanding of what we see from past experience (is that a tree on the horizon or a pylon?). We can’t look in two directions at once, we have to take time to construct the picture (we look over here, then over there – even if we don’t move our head, our eyes scan the scene).
Yet we perceive this as experiencing the landscape in ‘the present’. This is sometimes called the ‘spurious present’ – “the interval of time such that events occurring within it are experienced as present”. This is by contrast to the ‘real present’ which is supposed to be dimensionless.
In the diagram, the point at which the two cones meet (at the observer) is supposed to represent the real (objective, dimensionless) present.

Wednesday, 8 August 2012

Spot the difference

In an infinite set of things, some will be what Turing called ‘arbitrarily close’ – in other words indistinguishable. How many will depend on our accuracy of observation.
To test this for yourself, see how many differences you can spot in the drawing below.

Time and multiple universes

An infinite number of universes which contain nothing is the same as one universe which contains nothing. In other words - nothing.
The same goes for identical universes. The idea of two identical universes is ridiculous. There can only be one universe until an event happens. Then, time is created and another universe along with it. Or – time is the same as a multiplicity of universes.
There can’t be a period of time in which nothing happens. A universe in which nothing happens has no time and so does not exist.
Adam and Eve had an infinite amount of time to live uneventful lives. It was not until they ate the apple that things stated happening – and time began.

Sunday, 5 August 2012

The Brick

In the 1950s an avant-garde artist makes his film ‘The Brick’. To make the film, he sets up a brick in artificial light and, with the camera on a static tripod, films it for one hour.
The film is rediscovered and shown in an art cinema. It causes a sensation and runs for a week. The projectionist is bored and sometimes runs the film backwards. Then he makes a still slide of the first frame and shows it for an hour.


Suppose we take a snapshot of the universe in State A, then another in State B. If A and B are indistinguishable then nothing has happened (or time has not passed – which amounts to same thing).
There are many objections to this thought experiment – eg:
1.   Where is the camera which takes the snapshot? Is it ‘outside the universe’?
2.   If time does not pass between State A and State B, how can we take the second snapshot?