Draining the River and Quivering the Arrow

[Philosophy Now]

Raymond Tallis against the ‘flow’ and ‘direction’ of time.

http://philosophynow.org/issues/95/Drai ... _the_Arrow

[DavidR]

According to Tallis, "rivers, unlike the water in them, do not flow – otherwise maps would be continually out of date". It's not clear exactly what he means by 'continually', but his remark would probably not be made by a canoeist with experience of descending the same river over the seasons and years. Where quite a lot of rivers are concerned, maps are generally out of date. Perhaps this is particularly true of any involving sand and gravel, but that's hardly a minority. Many rivers are effectively canalised, and the Thames may be carefully stabilised in Westminster pending some catastrophic flood, but one thing the Glasbury-Hay section of the Wye has in common with the Ganges is that every rainy season makes for a different pattern of islands and flow: you could not use the 1:25 000 to select a line through the rapids, or find out whether the backwaters connect. Which brings us back to what Tallis means by 'continually'. The more detailed the map of the river, and the more precise one's purpose with it, the quicker it will be said to be out of date. Over millennia, even the 1:25 0000 road maps are out of date about rivers, and not just pubs, bypasses, cities and the like. But that's OK, because without saying exactly what he meant by this, Tallis specified that for any phenomenon to correspond with talk of flowing rivers would be to make maps not just out of date, but *continually* out of date. Well, if it rained in Builth Wells between the survey and the print run, the OS 1:25 000 will be 'continually' out of date.

[JohnElliott]

The author would enjoy talking to a relativity physicist about this topic. The well substantiated view of Einsteinian physics is that space-time is indeed a 4 dimensional structure in which the fourth dimension of time has units of metres, like the other three. We (and the whole of our "present" or "now" 3D space) are all travelling along the fourth dimension at the speed of light, which is why that dimension appears to us to have units of seconds rather than metres, since distance x=ct where c is the speed of light. That is why our world appears to be constantly changing and giving us the concept of time "flowing". In the Einstein view, c is a universal constant simply because it is the conversion factor for getting from seconds to metres or vice versa. When we achieve speeds in our 3D world approaching that universal speed c, we start to see strange effects like clocks going slow or distances getting shorter, all well-attested phenomena. We are fooled into thinking that time is something different in kind from space just because we so rarely encounter speeds that cause such effects. The GPS system however has to correct for such effects on a daily basis to maintain its locational accuracy.
A stimulating article - thank you.