4 ms·

My point is this: if you make a 1-inch model of a cruise ship (real length, ~1000 feet) and put it in a water tank which is approx. 120 feet in length (1/12000

by Pamar 3y ago

My point is this: if you make a 1-inch model of a cruise ship (real length, ~1000 feet) and put it in a water tank which is approx. 120 feet in length (1/12000 of the distance between Rome and the eastern coast of Sardinia) you can then make your ship model move at a decent speed just by dropping tiny quantities of liquid soap right behind the stern. How much soap do you need to replicate the effect with a real boat? The different scales (not only in terms of space/number of inhabitants, but also in terms of time) at which a household operates, compared with even the tiniest nation (Vatican City: 19 km2, 510 inhabitants, >1000 years of "life") invalidates any attempt to try to derive anything useful from the household model, precisely like the soap experiment I described above.

mejutoco 3y ago
I agree with you and the examples you mention. At the same time I am not disappointed that the model/analogy does not work in all cases. That does not mean it is not illuminating in others. Following your example (kind of, with planes). Dont people use wind tunnels to test aerodynamics of planes? Miniature planes/boats might be useful to detect design flaws early on. In that sense you can derive useful things from that model. The same model of a small boat will be useless to decide the route, the weather, or the electronics on board.
- Pamar 3y ago
  Not really, no. The example I used (based on this: https://www.scientificamerican.com/article/surface-tension-science-build-a-raft-powered-by-soap/ https://www.scientificamerican.com/article/surface-tension-s...) is precisely to show that if you play with scale too much, you might introduce (or remove) phenomena that make the whole model totally inapplicable. - a 1-inch cruise ship (model) can definitely be moved by 1 drop of dish soap. - 12000 drops of liquid dish will have no effect whatsoever on a full-sized cruise ship. Let's go back to our "State economy is just like a household economy". If you google for "major expenses of local government" you will get something like: "public school system, law enforcement, fire protection, public facilities , and public health." do you really believe that the household budget for "fire protection" or "law enforcement" is comparable (as a percentage of total expenses) to what a state spends? (According to the California State Controller's Office, in the 2021-22 fiscal year cities spent $14.82 billion on police expenditures, making up the highest category of spending at 14.8% of total expenditures in the state) Does the average household spend 15% of its annual budget on enforcing corrective measures to be applied to the family itself?! Same applies to income, actually. States have taxes, and may have some sort of natural resource that they can sell or "lease" to private companies for a fee. Something that is really difficult to shoehorn in something remotely similar at the household level. The only "insight" we can obtain from something like a "household economy model" is that if you spend more than what your assets are you will end in debt. Not exactly unexpected. But any kind of measure you might find useful at the household level (e.g.: everyone will fast by skipping 1 meal / week, reducing groceries bills by 7% - nothing to sneeze at, at the household level: https://www.statista.com/statistics/237211/average-food-expenditures-of-united-states-households/ https://www.statista.com/statistics/237211/average-food-expe...) will not really work at the city level, let alone at the state level. And it is not that difficult to understand why, either: enforcing the new law "absolutely nobody will have lunch on wednesday" will be complicated and expensive to enforce at the state level, and require more resources to be devoted to this new task, possibly resulting in a negative gain.
  - mejutoco 3y ago
    I agree with you with it on the scale example. Thanks for the detailed explanation. Where we disagree fundamentally is that you are finding that the analogy is wrong. But wrong for that? For the scale example it is wrong. For the aerodynamics testing on a little model it is not. From that, I conclude that it _can_ be useful, which is a different claim that it _always_ is.

by Pamar 3y ago

mejutoco 3y ago

I agree with you and the examples you mention. At the same time I am not disappointed that the model/analogy does not work in all cases. That does not mean it is not illuminating in others. Following your example (kind of, with planes). Dont people use wind tunnels to test aerodynamics of planes? Miniature planes/boats might be useful to detect design flaws early on. In that sense you can derive useful things from that model. The same model of a small boat will be useless to decide the route, the weather, or the electronics on board.

Pamar 3y ago
Not really, no. The example I used (based on this: https://www.scientificamerican.com/article/surface-tension-science-build-a-raft-powered-by-soap/ https://www.scientificamerican.com/article/surface-tension-s...) is precisely to show that if you play with scale too much, you might introduce (or remove) phenomena that make the whole model totally inapplicable. - a 1-inch cruise ship (model) can definitely be moved by 1 drop of dish soap. - 12000 drops of liquid dish will have no effect whatsoever on a full-sized cruise ship. Let's go back to our "State economy is just like a household economy". If you google for "major expenses of local government" you will get something like: "public school system, law enforcement, fire protection, public facilities , and public health." do you really believe that the household budget for "fire protection" or "law enforcement" is comparable (as a percentage of total expenses) to what a state spends? (According to the California State Controller's Office, in the 2021-22 fiscal year cities spent $14.82 billion on police expenditures, making up the highest category of spending at 14.8% of total expenditures in the state) Does the average household spend 15% of its annual budget on enforcing corrective measures to be applied to the family itself?! Same applies to income, actually. States have taxes, and may have some sort of natural resource that they can sell or "lease" to private companies for a fee. Something that is really difficult to shoehorn in something remotely similar at the household level. The only "insight" we can obtain from something like a "household economy model" is that if you spend more than what your assets are you will end in debt. Not exactly unexpected. But any kind of measure you might find useful at the household level (e.g.: everyone will fast by skipping 1 meal / week, reducing groceries bills by 7% - nothing to sneeze at, at the household level: https://www.statista.com/statistics/237211/average-food-expenditures-of-united-states-households/ https://www.statista.com/statistics/237211/average-food-expe...) will not really work at the city level, let alone at the state level. And it is not that difficult to understand why, either: enforcing the new law "absolutely nobody will have lunch on wednesday" will be complicated and expensive to enforce at the state level, and require more resources to be devoted to this new task, possibly resulting in a negative gain.
- mejutoco 3y ago
  I agree with you with it on the scale example. Thanks for the detailed explanation. Where we disagree fundamentally is that you are finding that the analogy is wrong. But wrong for that? For the scale example it is wrong. For the aerodynamics testing on a little model it is not. From that, I conclude that it _can_ be useful, which is a different claim that it _always_ is.