"They are damages or diseconomies sustained by the economy in general, which under different institutional conditions could be avoided. if these costs were inevitable under any kind of institutional arrangement they would not really present a special theoretical problem. to reveal their origin, the study of social costs must always be an institutional analysis. Such an analysis raises inevitably the question of institutional reform and policy."

“Had there been a computer in 1872... it would probably have predicted that there would be so many horse-drawn vehicles that it would be impossible to clear up all the manure.”

“Capitalism must be regarded as an economy of unpaid costs, ‘unpaid’ in so far as a substantial portion of the actual costs of production remains unaccounted for in entrepreneurial outlays; instead they are shifted to, and ultimately borne by, third persons or by the community as a whole.”

“Whenever social costs are shifted onto economically and politically weaker sections of society without compensation, a redistribution of the costs of production, hence real income is involved.”

“Social costs... are all direct and indirect losses sustained by third persons or the general public as a result of unrestrained economic activities.”

“To ignore social costs because they require an evaluation by society... and to leave social losses out of account because they are 'external' and 'non-economic' in character, would be equivalent to attributing no or ‘zero’ value to all social damages which is no less arbitrary and subjective a judgement than any positive or negative evaluation of social costs.”