...a classic non-sequitur. Nor are economic experiments entirely impossible as you claim, especially on the micro level (doubt me? A guy just won the nobel prize for devising means of doing so a couple years ago). Returning to the point though, it simply does not follow from the _limitations_ of economic experimentation that ex post facto conclusions (read: experience itself) are unreliable. In fact, the innovative driving agent of economic growth is of such a nature that it can ONLY be known ex post, never ex ante - go read Schumpeter.
If one could start from the beginning and implement a different policy one may be able to drawn sound conclusions but as the case maybe they are only opinion buttressed by theory.
Tf one were to take the inanity you posted above to its logical extreme it could be said that we do NOT know communism killed the Soviet Union since there is no alternative can be tested from the beginning in 1917 for comparison. Using your reasoning we're just as right (or wrong depending on how you look at it) to dismiss the Soviet failure as a product of excess fluoride in their water, or perhaps something culturally with Russians, as something inherently wrong with communism. But that, of course, would be absurd and so is your bizarre insistence that we cannot intellectually evaluate the policy of protectionism in the early 19th century (unless, of course, that evaluation supports your desired outcome of vindicating the tariffs - and no credible study does).
If you see something fundamentally wrong about the throng of scholars who have concluded protectionism was a dismal failure, why not write it up and get yourself published? Simply dismissing results that you disagree with out of hand over a pretended and logically absurd quibble with the fact that they attempt to evaluate the policy itself won't cut it though.
We are speaking of macro-economics here not micro invalidating your objection.
And many sources of economic growth are known while the growth is proceeding not only after. When cotton growing became profitable after the gin it was obvious to many then not merely after. Besides if your contention were true it only underlines my point and makes the choice of any policy a blind shot.
It is no inanity to point to the lack of replicatibility in economic history as a weakness in trying to make economics a science like chemistry. Nor is it an inanity to point to the fact that a different set of people using the same goals and tools will arrive at a different result.
To take the highly refined assumptions of an econometric study as productive of indisputable truth is inanity.
Communism, as theorized by Marx, was not what was seen in the USSR since his theory was to be applied in an advance capitalist society not a backward one. Its fall was the result of political issues as much as economic just as the American Revolution came about because of political issues more than economic.
Tariff issues are NOT just economic but often primarily political. Economists arguing that they don't work economically ignore the political aspects. Also ignored is the fact that there was NO Free Market for the Americans to compete in. They faced closed markets in most commodities in a world divided into Empires. Nor do they consider the willingness and ability of the older nations to glut the American markets and destroy the competition. One writer in the 19th described the process in the following words: "...it is notorious that great sums of money were expended by the British to destroy our flocks of sheep, that they might thereby ruin our manufactories. They bought up and immediately slaughtered great numbers of sheep; they bought our best machinery and sent it off to England, and hired our best mechanics and most skillful workment to go to England, simply to get them out of this country, and so hinder and destroy our existing and prospective manufactures."
You used Taussig to support your argument that the tariffs were counterproductive wrt iron but why don't we see what he said about cotton manufacture? After 1808 a period of restriction began which impeded then entirely prevented the importation of cotton goods. "In 1809 the number of mills built shot up... During the War (of 1812) the same rapid growth continued,.... These figures cannot be supposed to be at all accurate; but they indicate clearly an enormously rapid development of the manufacture of cotton." After the war ended and foreign competition began again domestic manufactures collapsed and many mills were abandoned. Congress responded with a tariff including a minimum valuation proviso which once again returned the sector to profitability. Taussig did NOT conclude the tariff was counterproductive as you implied in your iron example but merely that it was of mixed result helping some protected industries but not others.
Another statement he makes also supports my argument: "Conjecture as to what might have been is dangerous, especially in economic history, but it seems without a jar, the eager competition of well-established English manufacturers, the lack of familiarity with the processes, and the long-continued habit, especially in New England, of almost exclusive attention to agriculture, commerce, and the carrying trade, might have rendered slow and difficult the change, however inevitable it might have been, to greater attention to manufactures. Under such circumstances there might have been room for the legitimate application of protection to the cotton manufacture as a young industry."