“When the “environmental revolution” arrived in the 1960s, economists were ready and waiting. The economic literature contained an apparently coherent view of the nature of the pollution problem together with a compelling set of implications for public policy. In short, economists saw the problem of environmental degradation as one in which economic agents imposed external costs upon society at large in the form of pollution. With no “prices” to provide the proper incentives for reduction of polluting activities, the inevitable result was excessive demands on the assimilative capacity of the environment. The obvious solution to the problem was to place an appropriate “price,” in this case a tax, on polluting activities so as to internalize the social costs. Marshall and Pigou had suggested such measures many decades earlier. Moreover, pollution and its control through so-called Pigouvian taxes had become a standard textbook case of the application of the principles of microeconomic theory. Economists were thus ready to provide counsel to policy makers on the design of environmental policy.”

Source: Contributions to Modern Economics (1978), Chapter 7, Marx, Marshall and Keynes, p. 75

"The Effect of Government on Economic Efficiency." 1988

Martin Feldstein (1989), Foreword to New Ideas from Dead Economists by Todd Buchholz.

Quotes, NYU Law School speech (2006)
Context: For the last fourteen years, I have advocated the elimination of all payroll taxes — including those for social security and unemployment compensation — and the replacement of that revenue in the form of pollution taxes — principally on CO2. The overall level of taxation would remain exactly the same. It would be, in other words, a revenue neutral tax swap. But, instead of discouraging businesses from hiring more employees, it would discourage business from producing more pollution.
Global warming pollution, indeed all pollution, is now described by economists as an "externality." This absurd label means, in essence: we don't need to keep track of this stuff so let's pretend it doesn't exist.
And sure enough, when it's not recognized in the marketplace, it does make it much easier for government, business, and all the rest of us to pretend that it doesn't exist. But what we're pretending doesn't exist is the stuff that is destroying the habitability of the planet.

"Uncertainty, Evolution, and Economic Theory", 1950

What the Health (2017)

"The Pope & the Market," The New York Review of Books, October 8, 2015

Speech to the UN General Assembly (7 December 1988)
Context: We are witnessing most profound social change. Whether in the East or the South, the West or the North, hundreds of millions of people, new nations and states, new public movements and ideologies have moved to the forefront of history. Broad-based and frequently turbulent popular movements have given expression, in a multidimensional and contradictory way, to a longing for independence, democracy and social justice. The idea of democratizing the entire world order has become a powerful socio-political force. At the same time, the scientific and technological revolution has turned many economic, food, energy, environmental, information and population problems, which only recently we treated as national or regional ones, into global problems. Thanks to the advances in mass media and means of transportation, the world seems to have become more visible and tangible. International communication has become easier than ever before.

The Reason and the objective of Education Reform