the discovery of a 140 year old supernova reminds me of a statement i heard julian barbour make – but i can’t recall where it was. to paraphrase, he said that we have come to know the age of the earth by studying rocks that exist right now.
last semester i asked some students to consider these quotes by C.S. Peirce:
The following quotes are from Charles S. Peirce, American Philosopher, 1839 –1914, and come from Philosophical Writings of Peirce, edited by Justus Buchler. Available via Google Books.
“It is a matter of real fact to say that in a certain room there are two persons. It is a matter of fact to say that each person has two eyes. It is a matter of fact to say that each person has two eyes. It is a matter of fact to say that there are four eyes in the room. But to say that if there are two persons and each person has two eyes there will be four eyes is not a statement of fact, but a statement about the system of numbers which is our own creation.” p. 59
“..for the real is that which insists upon forcing its’ way into our recognition as something other than the mind’s creation. The real is active; we acknowledge, in calling it the actual. (This word is due to Aristotle’s use of action to mean existence, as opposed to a mere germinal state.)” p. 79
“The reality of things consists in their persistent forcing themselves upon our recognition. If a think has no such persistence, it is a mere dream. Reality, then, is persistence, is regularity. In the original chaos, where there was no regularity, there was no existence. it was all a confused dream. This we may suppose was in the infinitely distant past. But as things are getting more regular, more persistent, they are getting less dreamy and more real” p. 358
Nassim Taleb, from The Black Swan:
“Platonicity[ed. you’ll notice julian barbour’s site is called platonia]: the desire to cut reality into crips shapes….Categorizing is necessary for humans, but it becomes pathological when the category is seen as definitive, preventing people from considering the fuzziness of boundaries, let alone revising their categories.” p. 15
these thoughts are with me now while considering the different but related acts of the geologist (or anyone, for that matter) holding something in their hands (actual) and then studying (germinal) that thing, and then struck by how the result of that study, in this particular case, is a numerical value. …But to say that if there are two persons and each person has two eyes there will be four eyes is not a statement of fact, but a statement about the system of numbers which is our own creation.
the recent image of the supernova is actually a composite of two images, a radio image from 1985 (blue), and an x-ray image from 2007:
“the past isn’t even past” Faulkner