You argue that one dimension is not possible, as it cannot describe things that take up space. You define space as three dimensional. Then of course one dimension cannot describe three dimensional objects. However, three dimensions CAN do so just fine, obviously.

Secondly, you talk about different co-ordinate systems, such as diamond or watermelon. You’re misunderstanding what three dimensions as a measurement system means: it is indeed an arbitrary parametrisation of space, and any other co-ordinate system is just as good. There are in fact well-defined mathematical transformations that convert between different co-ordinate systems. In ALL such systems, however, there are three linearly independent quantities — even if you used five numbers to label positions, if you know three you can calculate the other two. This is what three-dimensional means — it is certainly NOT a statement that you can only move cubically.

Time is labelled as a dimension because it behaves just like one. To specify the location of an object, you need to say where in space AND time it is — otherwise, you might go and look after someone has already moved it! Furthermore, time is treated exactly equivalently to space mathematically, and at speeds near the speed of light, the apparent distinction between the two breaks down.

You argue that Einstein shouldn’t be allowed to make sweeping statements just because he knows more maths. I agree. But we take his statements seriously *because they alone agree with experiment*. The statements of the previous paragraph are tested every day in particle accelerators. The GPS system requires general relativity to function correctly. The motion of the planets can only be explained using relativity. Experiment, and experiment alone, can determine which theories are correct — and Einstein’s meet this test.

Lastly, you say that “down” does not exist if gravity is a bending of spacetime rather than a force. This is not true — down is very well defined in relativity, it is the direction of geodesic flow. Which requires some mathematics to define further, but it is very well defined, and agrees with your intuitive notion of down.

So thanks for your comments, and for thinking on these issues! There are many books that deal with these issues more, let me know if you’d like some suggestions!

]]>thanks for your “time” I hope this was helpfull

Maximo ]]>

Good to see you posting again Paul! Keep it up :)

]]>