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Though much is taken, much abides And though we are not now that strength Which once moved heaven and earth That which we are, we are One equal temper of heroic hearts Made weak by time and fate But strong in will To seek, to strive, to find And not to yield -- Tennyson, from "Ulysses" |
| date | 2000-11-17:14:52 |
| Metaphysics |
To what in reality does POSSIBILITY refer? Three types: 1) Principle possibility 2) Logical possibility 3) Physical possibility ======================== Principle Possibility We often say that something is possible "in principle" if we want to ignore some physical limitations that are accidental consequences of physical laws. For example, it is possible, in principle, to make a material with a yield-strength a million times that of steel. We would have to find a way of increasing the strength of the electro-magentic force to do so, perhaps, but what is meant is that there is no physical law that would be violated, nor is there any logical contradiction entailed, by the existence of such a thing. In contrast, it is not possible, even in principle, to know at the same time both the position and momentum of an electron to better than the limits imposed by the uncertainty principle. ========================== Logical Possibility Things are logically possible if there is no contradiction involved in their being so, and logically impossible if there is. Knowing what the moon looks like when no one is looking at it is usually given as a logical impossibility (if we include indirect means of observation such as cameras etc.) although in fact it is nothing of the kind. A person with three hands, or one that reproduces by binary fission, is logically possible, although not very interesting. =========================== Physical Possibility Things are physically possible if they can actually be done with today's technology. It is not physically possible to build a commercially viable orbital booster. It is physically possible to build a supersonic aircraft. Previously I've used "physical possibility" to refer to "principle possibility" but I think this language is better. =========================== Why knowing what the moon looks like when no one's looking at it is not a logical contradiction: It's all about "when". Distant observers detect the light reflected off the moon a long time after it has been reflected off the moon. So it is easy for a distant observer to detect light reflected from the moon at a time when no one was looking at the moon. What is impossible is to know what the moon looks like when no one can look at the moon, where "can" means "can in principle" look at the moon. Locking the moon up in a box doesn't stop anyone from looking at it; they just need technology that can see through the box, and any box we know how to build we know how to see through. But quantum mechanics provides a box that is made impenetrable by physical law. =========================== What, if anything, does all this have to do with the idea that human actions "could have been different" when we talk about free will? I have no idea. |
| Humans |
Are men no longer expected to carry stuff in their pockets? I ask this on the occassion of having to sew up the bottom of a pocket on a fairly new pair of pants. Admittedly I carry a couple of sets of keys and a fairly hefty pocket-knife there, but it seems to me the fabric should be able to stand up to that kind of load for more than a couple of months. This isn't the first time this sort of thing has happened, either. Women's clothing, I understand, has long been pocket-deficient, but I've noticed a decline in the pocket-quality of men's clothing as well in recent years. O no! I just realized I've said, "Y'know, things just ain't as good as they wuz when I wuz a boy." This was a temporary lapse of reason: I am not getting old! |
| Poem |
Tennyson's "Ulysses" is one of my favorite poems, and expresses one of the constants in my life: the desire to know, "to seek, to strive, to find, and not to yield." I have felt this, and it's kept me going, even when I have been made weak by lots of things. But as I've grown wiser what I'm seeking has changed, or at least expanded. Now, today, I'm seeking experience: joy and laughter and fun and pleasure as much as knowledge and learning. Carolyn has taught me how important that is. |
| Reading |
So what about Arthur and Achilles? Both are heros seen from the tail-end of a dark age. Dark-age Greece was considerably blacker than dark-age England. The fall of Mycenae was complete: writing--in the form of the difficult and complex Linear A and Linear B scripts--was lost entirely, and the archeological evidence suggests that after the fall of cities life was incredibly hard for the surviors. For around 300 years between 1050 BCE and 750 BCE the Greek world was a wreck, and Homer wrote very near to the end of that time, almost certainly drawing on a long oral tradition. He may indeed have been a member of the first generation of poets who learned alphabetic writing from the Pheonecians. Arthur is a character of Dark Age Britain, based loosely on the exploits of (probably) a Romano-Britain soldier/leader a century or two after the Roman withdrawl in the early 400's CE. After the Roman army went home, increasing pressure from Picts and Celts to the north and Saxons to the east led to the collapse of Roman culture, cities, commerce and most importantly the system of roads and communication. The dark age in Britain lasted around 600 years, but due in part to the moderating influences of the church it was never quite so complete as the Greek dark age. Mallory, from whom we get our "modern" Arthur drew on a rich pre-existing tradition, much of it French, and for some of which we have literary evidence. We can therefore see some of the structural machinations the story went through as it accreted from independent tales and Arthur was slowly eclipsed first by Gawain and eventually by Lancelot as the active center of the tale. Because there is no literary evidence pre-dating Homer, we can only guess at how his tale may have evolved, but this is what makes this sort of thing fun: speculation dressed up as scholarship. Which is fine, so long as we remember that it is just speculation, and in the absence of more evidence will never be anything else. Given the way these stories get transmuted, I wonder if the Iliad started out as a tale of the fall of cities, if it wasn't a collection of exploits of marauding bands of brigands who either caused, contributed to or benefitted from the collapse of civilization. Although the Greeks are nominally city-dwellers themselves, we never see them as such, and the city-dwelling Trojans are the enemies of all things Greek. Likewise, it's by no means obvious that Arthur had any use for Christianity; he could as well have been a pagan trying to hold together a world being torn apart by the impossible doctrines of the church as a Christian trying to convert, unify and rule the heathens. Although considerably less episodic than the Arthurian tales, the Iliad still contains some evidence of being stitched together. I wonder if there isn't a lost saga of Diomedes somewhere in its ancestry, for example. I'm sure that, like every possible aspect of these stories, this sort of similarity has been considered somewhere by someone far more knowledgeable than me. But it's still fun to wonder. |