Kate tucked into the DLC for Anno 117: Pax Romana, Dawn of the Delta. How does it stack up? Here are our impressions of this Egyptian-flavored DLC.

This Maps item is sold by SourisdesMoissons. Dispatched from United Kingdom. Listed on 30 Oct, 2026

YouTube video by Nina Paley

Cultural forces under the Ptolemaic dynasty briefly allowed scholars like Herophilus to practice dissection—and possibly vivisection—on human subjects.

YouTube video by Sand Pebbles

Like the previous Ptolemaic model, Copernicus’ heliocentric model of the solar system required epicycles to predict the astronomical observations of the positions of the planets in the night sky. (The reason was that Copernicus’ orbits were circular instead of elliptical, and I suppose he needed epicycles to simulate the ellipticality.) Indeed, by Gingerich’s count, the Copernican system had _more_ epicycles than the Ptolemaic. What advantage did the Copernican theory have over the Ptolemaic, then? The Copernican theory did not need epicycles to predict the _qualitative_ movements of the planets in the night sky, with the famous retrograde motion where sometimes planets move from night to night in the opposite of their usual direction. Such qualitative features are nicely accounted for by the fact that the planets, including earth, are all orbiting the sun, and thus sometimes the earth overtakes a slower outer planet which thus appears to be moving backwards. On the other hand, Ptolemaic theory is both quantitatively _and_ qualitatively wrong without epicycles: it needs epicycles to predict the existence of retrograde motion. We think of the Copernican theory as superior due to its greater simplicity. But the theory as a whole is not simpler. However, it provides a simpler explanation of a puzzling or significant phenomenon. This suggests an interesting theoretical virtue, which we might call not just parsimony, but _explanatory_ parsimony, where the theory offers a particularly parsimonious explanation of one or more specific phenomena against a competitor, even if there happens to be little difference in the theories’ overall parsimony as needed for explaining _all_ the phenomena, and even if there is _less_ overall parsimony, as Gingerich claims was the case for Copernicus. Take a more human case. We could explain the assassination of JFK in terms _S_ 1, a theory about Oswald working alone, or we could explain it in terms of, _S_ 2, where Oswald is working together with the CIA. The non-conspiracy explanation is more parsimonious: it involves two persons—Oswald and JFK—as opposed to many more. But notice that neither _S_ 1 nor _S_ 2 is capable of explaining all the humanly significant phenomena of 1963. To that end, both theories need to be enriched to include the activities of all of the 3.2 billion people of 1963. Let _T_ 1 and _T_ 2 be such respective enrichments of _S_ 1 and _S_ 2. These are vast theories. Is _T_ 1 more parsimonious than _T_ 2? I doubt it. After all, the people at the CIA who, according to _S_ 2, were working with Oswald were still doing _something_ according to _T_ 1, and indeed something that explains events of human significance. This activity is included in _T_ 1. Theory _T_ 1 superior to _T_ 2 not in terms of overall parsimony—or even the overall parsimony of the explanatorily fundamental posits—but in terms of how large a portion of (or approximation to?) the theory is needed to explain the specific events around the assassination of JFK. On _T_ 1, a much smaller theory (with primary focus on two persons) _S_ 1 is sufficient for the assassination, while on _T_ 2, a much larger portion _S_ 2 is needed. If this is right, then we like _focused_ explanations to be neater and smaller, even if the overall story is equally complex. Here is an interesting application. Physicists have a strong preference for local theories, in the broad sense of the word according to which the behavior of a system depends only on what is happening near the system. But notice that in practice locality is often an approximation. Each system is affected _to some degree_ by everything in its past light cone. To get a full explanation of the system, we need the whole past light cone. But we still have locality, because we get explanations of how the system works to a high degree of approximation in terms of how things are nearby, because all of the forces of physics drop off with distance. A preference for locality is thus a special case of a preference for explanatory parsimony: we want the _approximate_ behavior of the system to have a more parsimonious explanation, even if the fully precise behavior needs a profligate one. The general feature thus is this. It counts in favor of a theory if a puzzling or significant coarse-grained feature of our observations is explained in a more parsimonious way according to the theory, even if there is no parsimony advantage with respect to finer grained observations. From a Bayesian point of view, this translates into a view on which we should have higher priors for theories that explain more of puzzling or significant phenomena with less. Is the anthropocentrism in the notion of “puzzling or significant phenomena” a problem? Maybe not on my natural law epistemology: our epistemology is human epistemology. I wonder if there is a philosophy of religion application. For instance, consider that theism provides a parsimonious explanation of the coarse-grained fact that there are rational animals: a perfect being has good reason to create rational animals given the objective value of such animals. But once we look at more fine-grained facts, such as that the rational animals have ten fingers and ten toes, it can be contended that we no longer have a more parsimonious explanation. Indeed, to explain all the details of humans, the theist is likely to need to invoke evolutionary mechanisms just as the naturalist does. Could the theist say that the more parsimonious explanation of the coarse-grained fact still counts for something?