Raff

but when in practice we know that this basic premise is false

Without doing an experiment in which a single variable is changed that is opinion not fact. Japan became an industrial super power using exactly this methodology.

I should clarify slightly, when resolving a process problem standard practice is to change one variable at a time, something the Japanese exploited first of the industrial nations.

Sandy, yes of course the ideal is to change one thing keeping everything else constant and see what happens. But economics is fundamentally about people and psychology plays a big part. There's no such thing as keeping everything else constant when people can change their behaviour as a result of your single change. Quite apart from the fact that the economy is not static but constantly changing in cycles of boom, bust and everything in between. It is not really possible to argue against this; I don't know why anyone would bother.

So GWPF today is pushing for investment of foreign aid money in adaption to climate change. Ok it wants this to be instead of investing in renewables, but it is nice to see that they approve of foreign aid. I imagined they would not. Of course they play their part as the coal industry's cheerleader by bemoaning the World Bank's refusal to finance coal-fired power plants, but then they fail to call for investment in such plant. Where's the sense in that? If they want investment in coal to support their friends in coal industry why the double talk - they only call for "the Green Climate Fund to help poor countries adapt". Strange.

Raff

Give some proof that the GWPF is funded by Big Coal. Real proof not Robert Brulle "proof" by once having been seen talking with someone with a coal fire proof.

Raff

But economics is fundamentally about people and psychology plays a big part. There's no such thing as keeping everything else constant when people can change their behaviour as a result of your single change.

Surely that is the whole point, change one thing and see what happens?

Raff,
The GWPF very carefully made sure that they received no funds from the fossil fuel industry. For you to claim that support of the coal industry is their motivation is something you should substantiate or retract.
Even then, if somebody's motivation for support of a position is mpure from your point of view does not mean they are wrong. Neither does someone sharing your point of view mean that they are right on everything. This sort of nonsense is the reason for much of the polarized thinking. Shared unquestioned beliefs is also why the climate consensus has failed to advance in the past twenty years.
This issue is nothing new. Suggestion of people lying, or being blinkered by their beliefs, has been practised for millenia. That is why Matthew 7:3-5 should always be borne in mind before making such allegations.

I said nothing of GWPF being funded by coal. You are perhaps imprinting what you believe to be true on what I actually said. That said, there is an industry of organisations that exist to prevent traceability of donations (as recent leaks have shown), so GWPF's promises are likely to be worthless.

Sandy, it is too simplistic to think that people in aggregate react to a single marginal policy change in an observable way. They react to all sorts of stimuli pulling in differing directions. There are always confounding factors that complicate analysis of the effects of policy changes. As a result, beyond the basics, there seem to be few aspects of economics that are agreed upon broadly across the political spectrum of economists.

Raff
Recommended Reading (Free for Kindle)

Raff,
Read what you say in reply to my comment. You are saying that a number of distinguished people are behind a conspiracy. You do not have evidence, just your logic based on the fact they disagree with you. Even if you were Albert Einstein, what you present is still hearsay evidence. What is more it is not relevant to whether the GWPF is wrong in their views. If people who have blinkered views are always wrong, how come the V1 and V2 rockets worked in WW2?
Actually there is a counter-argument. The people that are often the most wrong on scientific views are those that believe in a particular hypothesis. Those who have strong beliefs elsewhere, or develop hypotheses to understand the world around them. will not worry so much if their hypothesis is overturned. Developing a hypothesis means building on, but modifying, what has gone before. Understanding why a hypothesis fails can lead to new hypotheses that enable us to better understand the world around us.

It is well known that various organisations exist for the sole purpose of hiding donations so that they are not attributable. There are those that do this for donors on the right; I would be amazed if equivalents didn't exist on the left.