Today is Pi day. Today is also the day when, for reasons best explained by bureaucrats and horology nerds, we 'spring ahead' into 'daylight saving time' (DST).
What is it about the progress of time that captures the attention of Homo Modernus? Parmenides spent most of his time trying to convince the ancient Greeks that time was a side-effect of imperfect sensory perception. Peoples throughout the last several thousand years have lived with no more accurate a timepiece than casual obervation of the sun.
In fact, it's only in the last several hundred years that this idea of 'accurate instruments' even entered into it. Not that the medievals were ambivalent about accuracy; on the contrary, they could quibble over minutia with the best of them. What I mean is that before the advent of trans-oceanic sea travel, there wasn't even any reason to care about time-keeping with any more accuracy than a few hours. Give a medieval the problem of calculating 'local noon-time' on a cloudy day, and they would probably ask "why would you need to know the position of the sun if it's cloudy?" Without faster-than-horse travel, even the question of keeping appointments is moot. You get there when you get there. Shops closed when people went away, or when the shop-keepers had better things to do, rather than by the arbitrary 5PM.
Sailing comes into it because of the problem of fixed points of reference in the middle of the sea-there aren't any. The only way to figure out where you are at sea (yes, even in the age of GPS) is to find a moving point of reference (the sun will work, or a government satellite) and then compare the time of your reading with the time from a known position. If the sun is at three PM where you are, and your clock says it's six PM in London, you can work out how far East of London you are. Really, clocks have always been most important for telling you what time it is somewhere else. (Alternatives to the second-accurate clock involed firing cannons into the air and conditioning dogs to feel pain at precise intervals...)
So, we take our watches out and we adjust our alarm clocks, just because someone somewhere decided that just sailing to the next harbor wasn't good enough; he had to know where he was so he could avoid sand-bars and cross oceans to conquer new worlds. Now we have fifteen-minute coffee breaks and per-minute phone billing and speeding tickets.
And if you believe Parmenides, there's no such thing as change or motion anyway.
I wonder if he came up with that idea to get himself out of a speeding ticket.
Pi, in contrast, has nothing to do with what's going on somewhere else, and everything to do with the world at hand. Pi never assumes that what's going on somewhere else is more important than what's going on right here. Pi is unconcerned with conquering foreign lands, or with speed through a construction zone. Pi does not change, and in that sense I'm sure Parmenides was a fan, but Pi is also at its most useful when you face an unfamiliar, change-ridden problem, like the area of your pizza pan. Parmenides might not have believed in the passage of time, but it's hard to argue with precisely-measured-and-distributed-and-melted cheese.