“三个水枪手”这期关于“润”的节目，吵得很是热闹。润，还是不润？余英时先生也曾面临过这个问题的拷问。 贾老师@jiajia 提到余英时1950年从香港返回北京的时候，刚好火车坏在一个叫“石龙”的小站，给余先生留下了“天人交战”的时间。他经过深入思考之后，当即决定返回香港，不再回大陆了。（贾老师说余英时从此没回过大陆，其实余先生1978年短暂访问过大陆一次） 余英时先生还提到他第一次从罗湖桥进入香港时，突然觉得“头上一松”，“整个人好像处于一种逍遥自在的状态之中”的奇异体验。 以上这些内容，都出自于我们出版的这本《余英时回忆录》之中。欢迎大家阅读😋 E169 我们又吵了:「应润尽润」现在还说得出口吗? 全球反移民后的灵魂拷问 | 移民 | 润学 | 签证倒计时 via @YouTube

Imagine being able to make stone translucent. Giovanni Strazza possessed that extraordinarily rare skill. His bust of the Virgin Mary, executed in flawless Carrara marble, is one of the most impressive feats by any sculptor. Strazza's "wet drapery" technique continued the legacy of previous Italian sculptors like Giuseppe Sanmartino, who produced mind-bending veils from marble a century earlier — the famous "Veiled Christ" is a canonical example. The tradition also dates back to much earlier sculptors known for carving intricate folds, in particular Renaissance artists like Michelangelo and ancient masters from Greece's Hellenistic period. But in the mid-19th century, Strazza took the technique to its extreme. The subtle layered effect he achieved allows the viewer to easily discern Mary's facial features from the delicate veil, and at the same time creates the illusion of total weightlessness. How he created something so soft and fluid from solid stone, using only basic hand tools, is a mystery.

Okay, time to explain the Imperial system, the metric system, and why attempts to replace either with the other are all retarded. They have two different purposes. The metric system is designed around precise measurement of objects. Its goal is to make engineering and scientific calculations simple. The Imperial system is designed around humans. Its goal is to make calculation unnecessary. 100 degrees is really hot. 0 degrees is really cold. Anything that starts with a 5 is cool, anything that starts with an 8 is warm. No computation. 6 feet is tall, 5 feet is short. 100 pounds is light, 200 pounds is substantial, 300 pounds is heavy. A 1000 square foot house is small, a 2000 square foot house is medium, a 3000 square foot house is large. 1 mile is a short walk, 2 miles is a medium walk, after that it takes a while. 1 acre of land is a homestead, 10 acres is an estate, 100 acres and up is a ranch or a farm. Do you see now why it is so strange and awkward to convert from miles to feet? It's because converting from miles to feet is not something you're supposed to do in the first place. Yes, they are both measures of length, so they are technically convertible, and yes, on rare occasions, you might need to do that. But feet are for measuring humans, and things built around humans, like doorways, and mattresses. Miles are for measuring travel distance. You wouldn't measure the distance between Seattle and Portland in feet for the same reason you wouldn't measure the distance between Tokyo and Osaka in mattress-lengths. It would be silly. This is why Americans so fiercely resistant to any notion of "conversion" to the metric system. Because it makes no sense. We already use the metric system for what it's good for, which is doing physics and chemistry and whatnot. But converting everyday measurements to the metric system would be less useful, generally inconvenient, and serve no purpose other than to make petty government bureaucrats happy that everything is now tidy, orderly, and worse, three qualities that bureaucrats love. I thought about this carefully when I wrote my first science fiction novel. In the world of the 22nd century, extraterrestrial settlers ("Orbitals") use three systems of measurement. They measure themselves in feet, inches, and pounds. They measure the spacecraft and habitats they build in meters and centimeters, grams and kilograms. And they measure space travel distances in light-seconds and light-minutes. Each system has its own natural scale. The sole exception to this is when Marcus doses himself with drugs for high-g resistance, Miranda objects that he has taken too much, and Marcus responds by stating his mass... in kilograms. Why? Because they're talking about drug doses, a engineering measurement. Drugs are dosed in milligrams per kilogram. So, yes, the Imperial system makes perfect sense when you understand what it's for, and no, we ain't changing. And, as a general rule, when an entire civilization of smart people does something for centuries, and it makes no sense to you, they're probably not being silly. It's more likely there's something you don't know.

Mathematica 15.0 出了，我又想起了高二时，我第一次接触 Mathematica 4.2 时的惊喜场景。 这版 Mathematica 能自动检测你机器上的 code agent，然后做相应的 MCP 配置安装。这个 MCP 支持直接生成 notebook。于是我让 Codex 分析了我一个 09 年写的 C++ 程序，把它转移成了 Mathematica 程序，完美。