Ernest Mandel quote: “For Marx, ‘pure’ economic theory, that is economic theory which abstracts from a specific social structure, is impossib…”

“Mainstream economics scholarship produces theory without facts ("pure theory") and facts without theory”

Michel Chossudovsky (1946) Canadian economist

"applied economics"
Source: The Globalization of Poverty and the New World Order - Second Edition - (2003), Chapter 2, Global Falsehoods, p. 27

“An important object of the Journal should be the publication of papers dealing with attempts at statistical verification of the laws of economic theory, and further the publication of papers dealing with the purely abstract problems of quantitative economics, such as problems in the quantitative definition of the fundamental concepts of economics and problems in the theory of economic equilibrium.
The term equilibrium theory is here interpreted as including both the classical equilibrium theory proceeding on the lines of Walras, Pareto, and Marshall, and the more general equilibrium theory which is now beginning to grow out of the classical equilibrium theory, partly through the influence of the modern study of economic statistics. Taken in this broad sense the equilibrium problems include virtually all those fundamental problems of production, circulation, distribution and consumption, which can be made the object of a quantitative study. More precisely: The equilibrium theory in the sense here used is a body of doctrines that treats all these problems from a certain point of view, which is contrasted on one side with the verbal treatment of economic problems and on the other side with the purely empirical-statistical approach to economic problems”

Ragnar Frisch (1895–1973) Norwegian economist

Frisch (1927). as quoted in: Bjerkholt, Olav, and Duo Qin. A Dynamic Approach to Economic Theory: The Yale Lectures of Ragnar Frisch. Routledge, 2010: About "Oekonometrika"
1920

“There [is]… a list of five tests which any body of doctrine which aspires to the name of economic theory must be able to meet:
1. Economic theory should unify economic science. - The task of a general body of theory in any subject is to give unity to its investigations…
2. Economic theory should be relevant to the modern problem of control. - Students of economics should spend their efforts upon subjects worth investigation…
3. The proper subject-matter of economic theory is institutions. - The demand that economic theory relate to institutions is implicit in the plea for its relevancy…
4. Economic theory is concerned with matters of process. - If economic theory is to treat of institutions it must know both the kinds of things institutions are and the kinds of things they are not…
5. Economic theory must be based upon an acceptable theory of human behavior.”

Walton Hale Hamilton (1881–1958) Yale Law Professor

After all control and institutions and processes are immediate things. They can all be translated into terms of human conduct...
Source: The Institutional Approach to Economic Theory, 1919, p. 311-6

“Such is the economic programme of State Socialism as adopted from Karl Marx.”

Benjamin Ricketson Tucker (1854–1939) American journalist and anarchist

¶ 11 & 12
State Socialism and Anarchism: How Far They Agree, and Wherin They Differ (1888)
Context: First, then, State Socialism, which may be described as the doctrine that all the affairs of men should be managed by the government, regardless of individual choice. Marx, its founder, concluded that the only way to abolish the class monopolies was to centralize and consolidate all industrial and commercial interests, all productive and distributive agencies, in one vast monopoly in the hands of the State. The government must become banker, manufacturer, farmer, carrier, and merchant, and in these capacities must suffer no competition. Land, tools, and all instruments of production must be wrested from individual hands, and made the property of the collectivity. To the individual can belong only the products to be consumed, not the means of producing them. A man may own his clothes and his food, but not the sewing-machine which makes his shirts or the spade which digs his potatoes. Product and capital are essentially different things; the former belongs to individuals, the latter to society. Society must seize the capital which belongs to it, by the ballot if it can, by revolution if it must. Once in possession of it, it must administer it on the majority principle, though its organ, the State, utilize it in production and distribution, fix all prices by the amount of labor involved, and employ the whole people in its workshops, farms, stores, etc. The nation must be transformed into a vast bureaucracy, and every individual into a State official. Everything must be done on the cost principle, the people having no motive to make a profit out of themselves. Individuals not being allowed to own capital, no one can employ another, or even himself. Every man will be a wage-receiver, and the State the only wage-payer. He who will not work for the State must starve, or, more likely, go to prison. All freedom of trade must disappear. Competition must be utterly wiped out. All industrial and commercial activity must be centered in one vast, enormous, all-inclusive monopoly. The remedy for monopolies is monopoly.
Such is the economic programme of State Socialism as adopted from Karl Marx.

“Hayek had high regard for Marx in technical economic theory and considered him a predecessor in his business cycle theory. […] It was not in technical economic theory that the classical Austrians disagreed with Marx. So towering a figure in history is Marx that discussion of his thought in summary form is always difficult, for there is so much that he said and that others have said about him. At the same time, so tendentious, ill-spirited, and just plain wrong a thinker was Marx that it is surprising that he may have had some of the influence attributed to him. Hayek’s opposition to Marx was in the realm of practical political emanations from Marx’s thought. Here he considered Marx’s influence to have been wholly pernicious.”

Alan O. Ebenstein (1959) American political scientist, educator and author

Hayek's Journey: The Mind of Friedrich Hayek (2003)

“Social reformers and legislators will never be economists, and they will always work on economic theory of one kind or another.”

Philip Wicksteed (1844–1927) English economist

Pages 22–23.
"The Scope and Method of Political Economy in the Light of the 'Marginal' Theory of Value and Distribution" (1914), §II
Context: Social reformers and legislators will never be economists, and they will always work on economic theory of one kind or another. They will quote and apply such dicta as they can assimilate, and such acknowledged principles as seem to serve their turn. Let us suppose there were a recognised body of economic doctrine the truth and relevancy of which perpetually revealed itself to all who looked below the surface, which taught men what to expect and how to analyse their experience; which insisted at every turn on the illuminating relation between our conduct in life and our conduct in business; which drove the analysis of our daily administration of our individual resources deeper, and thereby dissipated the mist that hangs about our economic relations, and concentrated attention upon the uniting and all-penetrating principles of our study. Economics might even then be no more than a feeble barrier against passion, and might afford but a feeble light to guide honest enthusiasm, but it would exert a steady and a cumulative pressure, making for the truth. While the experts worked on severer methods than ever, popularisers would be found to drive homely illustrations and analogies into the general consciousness; and the roughly understood dicta bandied about in the name of Political Economy would at any rate stand in some relation to truth and to experience, instead of being, as they too often are at present, a mere armoury of consecrated paradoxes that cannot be understood because they are not true, that every one uses as weapons while no one grasps them as principles.