shannonr asked: I asked before, but did ya go ahead and do that Google search I set you for homework?

Yes, I did the exact search you suggested, and the first reference that came up said almost exactly what Pablo said. Nothing else on the first page was relevant.

Shannonr wrote: And then you (in saying Pablo's "got the maths right") compare that with a single optional car journey. That is, in the specific terms of the example, three people choosing drive over fly.

No, the single car journey as hypothesized represents many such journeys in a reasonable way.

I did not say "got the maths right".

amity wrote: That explains it! My problem with your math is that I still naively believe that there's a difference between micro- and macro-economics.

from Wkipedia:

Microeconomics is a branch of economics that studies how individuals, households and firms make decisions to allocate limited resources,[1] typically in markets where goods or services are being bought and sold.

Microeconomics examines how these decisions and behaviours affect the supply and demand for goods and services, which determines prices; and how prices, in turn, determine the supply and demand of goods and services.

I would say that microeconomics is relevant.

also from Wikipedia:

Macroeconomics, on the other hand, involves the "sum total of economic activity, dealing with the issues of growth, inflation and unemployment, and with national economic policies relating to these issues"[2] and the effects of government actions (such as changing taxation levels) on them.[4]

I would also say that macroeconomics is not relevant. "Micro-level" and "macro-level" as used above are not the same as the terms used in economics.

Shannon, would you please post a link at your signature? One that you think explains your position well. I would be quite happy to read and comment here, or on the next appropriate article if this one gets closed down. It is not obvious to me that other factors come into play at such a level as to make Pablo's analysis worthless, and you have not demonstrated this.

I would appreciate that you keep your comments on my motivation to yourself. You haven't a clue.

If I owned a telecom, I would find it a violation of my rights that I would be required to provide NSA with a copy of all foreign to foreign communications on a routine basis. It is, after all, information that has been entrusted to me for safe passage. But I would worry more about how to give them the foreign to foreign without including a lot of other stuff as well. In fact, I would think that the information analysis necessary to do that on an email system would exceed what I ought to be doing in transferring such information.

Thanks, that was a very interesting post. The email situation is truly complicated. Suppose foreigner A sends a message to US citizen and resident B who forwards it it to foreigner C, perhaps adding something to it. What does the telecom send to the government? Nothing, I would say, but I bet NSA would say it must have at least the original part that that is an obvious attempt at foreign to foreign communication. But how is that supposed to happen? The telecom that has the forwarded message on his disk does not necessarily have the the original message from A. (B could have multiple accounts on different providers, forwarding A's message to himself before sending it to C.) So the telecom with the message that C will retrieve has no idea what he even has unless all providers access a common data base that cross references all accounts with the account holders.

So what is a telecom to do? What is a spy to do? The solution: everything goes to NSA and they figure it out. No chance of abuses, right?

wrote:

I've made my "position" as clear as I can. If you think it's worthwhile to compare three people not turning up for a scheduled flight, to three people carpooling across the country, in terms of emissions "saved" from that plane and "caused" by that car (not, note you well, an _average_ car to an _average_ flight), then I can't help you to get anywhere else.

1. The calculation in question is not limited in application to the quote above. You are misrepresenting its significance.

2. You claim there are links that support your position, urge me to go find them. But you are unable to provide even one. There aren't any, are there? How could there be? Your position is not coherent enough.

3. You do not have the necessary foundation in quantitative reasoning to understand how statistically derived rates can be used to generate valid hypothetical cases.