I think you're right in your assertion that the "dismal science" is cherry-picked to support a perspective, not unlike using hard science in the same way, but without the ability to reliably reproduce results.
That's why it is hard to take economists seriously. If economy is a science, then facts should establish themselves and economists should agree on more and more things. That does not seem to happen.
Take the statement "Lowering income taxes causes people to work more and in the end generates more revenue for the state". That theory has been put to test in many countries (like in the US during Reagan's presidency) but they still can't agree on if it is true or not. So how can economy be a science when empirical evidence doesn't cause facts to accumulate?
I recommend this article at The Atlantic about what economists agree on. It has citations to surveys of economists: http://www.theatlantic.com/business/archive/2012/04/4-politi...
Related but reductionist cartoon: http://www.smbc-comics.com/?id=3117
And contrary to popular belief, economists would generally agree that certain facts have established themselves and been agreed upon. For example, subjective value: https://en.wikipedia.org/wiki/Subjective_theory_of_value
This is an essential insight of economics, and one that was not really systematically grasped until recently (and still not grasped by the majority of the public.) It is as close to true as a sociological/ecological thesis can be, and is almost universally accepted. But because it is so accepted, you don't hear much about it.
What you're referring to is the Laffer curve - based on the observation that, at both 0% and 100% marginal tax rates, no tax revenue will be collected (none at 0% because no tax, essentially none at 100% because of disincentive.) That means that, in between those two end-points, there has to be a curve of some shape showing the total revenue collected, with a peak (or peaks) somewhere on it where revenue is maximized. The discussion is about where this peak is, and how the curve is shaped. To say "does lowering income taxes increase revenue" is an incomplete question: lower from what rate? Under what macroeconomic conditions? At what overall national wealth level? Interacting with what other taxes? Considering what conditions in capital markets? Etc, etc. Teasing out these huge numbers of other factors is the challenge of economic study, and why so many seemingly "simple questions" are unanswered: because they're not actually simple.
That's the point. Assuming the Laffer curve theory is correct, the question should be "what is the optimal tax rate?" That would mean that economists should propagate for the tax rate to be increased in some countries because it is too low and decreased in others. That's not what economists have been doing (if I'm wrong can you show me an economist favoring increasing taxes using the Laffer curve theory?) and instead they have only asked "how much lower should the tax rate be?"
Now the theory might be discredited, but I'm sure economists will come up with a new one to justify lowering taxes. :)
> Etc, etc. Teasing out these huge numbers of other factors is the challenge of economic study, and why so many seemingly "simple questions" are unanswered: because they're not actually simple.
But the questions aren't going unanswered. Politicians ask and economists do answer questions about tax rates, unemployment rates, interest rates, wage growth...
In climatology, at least the basic principles have been tested in laboratories; higher concentration of CO2 in air -> less reflected sunlight -> higher temperature. The Laffer curve theory was never tested in a laboratory, yet it was for decades trotted out as the truth by economists.
Here's a reasonably representative survey of US economists about the laffer curve: http://www.igmchicago.org/surveys/laffer-curve
Note what's happening here: most economists either think that a cut in federal income tax rates would lead to higher GDP, or are uncertain/think there's no effect. However, almost all also think that such tax cuts would not increase revenue - so any argument for tax cuts, according to these economists, is not based on the Laffer curve. Indeed, because of where these economists think US income tax rates are on the Laffer curve, they would have to agree, to be consistent, that increasing tax rates would increase revenue, on the margin. Therefore, the "Laffer curve consensus" among US economists is in fact the opposite of what your impression is.
> But the questions aren't going unanswered. Politicians ask and economists do answer questions about tax rates, unemployment rates, interest rates, wage growth... In climatology, at least the basic principles have been tested in laboratories; higher concentration of CO2 in air -> less reflected sunlight -> higher temperature. The Laffer curve theory was never tested in a laboratory, yet it was for decades trotted out as the truth by economists.
Politicians get certain answers to these questions from different economists, but they're definitely live issues in the field itself. Don't confuse the theory that Laffer curves exist - which is not controversial - with the argument that a particular tax regime is on a particular point of the curve - which is more uncertain. Just because you get an answer does not mean the question is definitively concluded.
And you can test the Laffer curve in a lab - but only with small numbers of people in a limited economic context. When you scale it up to a large number of people in a complex economy, the picture is much less clear and more complicated. (Likewise with climatology.) That's why it's hard!
Also, consider the following paper, written around the same time that people first started calling it the Laffer Curve (though the basic idea had been understood well before.): https://object.cato.org/sites/cato.org/files/serials/files/c...
It's by David Henderson for Cato, who's quite in favour of cutting taxes. But rather than jump on the argument as a useful "justification" for doing so, he points out the numerous limitations of the model, and the possibility of unusual Laffer Curve shapes that would mean tax cuts would not "pay for themselves." Again - don't confuse the non-controversiality of the existence of a Laffer curve, with the actual controversy over where, on what kind of a curve shape, current policy is located. (And whether maximizing tax revenue is even the correct policy.)
You're acting as though "economists" are all of a mind on this issue - they aren't. They generally agree on some fundamental analytical tools, but come to a range of answers based on how they use them and what information they have.
Reducing taxes does cause people to work more. Whether it results in more revenue for the state depends on how much income tax was before and after the change. Elasticity of labour supply is not constant over all tax rates.
I know people like to crap on the Laffer curve but they crap on it because it's trivial if you have the barest knowledge of economics, not because it's false.
Macroeconomics is closer to the morass you describe but it still accumulates truth, if possibly depressingly slowly and with thirty year periods of regress. Microeconomics is on much firmer ground, in large part because they have more data and it's easier to accumulate it.
If you want a very readable introduction to price theory, which is a large part of microeconomics check out "Hidden Order" by David D. Friedman. It's based on his Price Theory textbook but rewritten for interest and readability. If you want something a bit more mathematically sophisticated, (basic calculus) look at Intermediate Microeconomics, Hal Varian.
Is there any evidence to back that statement up?
This is not the best example. When a panel of economists was asked whether "a cut in federal income tax rates in the US right now would raise taxable income enough so that the annual total tax revenue would be higher within five years than without the tax cut," none of them answered in the affirmative. 8% said they were "uncertain," and 71% either "disagreed" or "strongly disagreed." (5% answered "no opinion" and the rest didn't answer at all.) See: http://www.igmchicago.org/surveys/laffer-curve
If you don't take economists seriously, you might not notice when they agree on things.
Let's say you create some sort of giant monetary stimulus package. If the economy gets worse proponents will say "Whew! Just think how terrible things would have been without our stimulus package," and opponents will say "Things got worse because of the stimulus package!"
There's no way to know who's right. The best you can do is make imperfect models to encapsulate trillions of individual decisions people make. But that's not proof.