The benefit principle differs radically from the two preceding criteria of taxation. For the sacrifice and ability-to-pay principles depart completely from the principles of action and the accepted criteria of justice on the market. On the market people act freely in those ways which they believe will confer net benefits upon them. The result of these actions is the monetary exchange system, with its inexorable tendency toward uniform pricing and the allocation of productive factors to satisfy the most urgent demands of all the consumers.

Equality of taxation has far more to commend it than any of the above principles, none of which can be used as a canon of taxation. “Equality of taxation” means just that—a uniform tax on every member of the society. This is also called a head tax, capitation tax, or poll tax. (The latter term, however, is best used to describe a uniform tax on voting, which is what the poll tax has become in various American states.) Each person would pay the same tax annually to the government.

A slogan popular among many “right-wing” economists is that taxation should be for “revenue only,” and not for broad social purposes. On its face, this slogan is simply and palpably absurd, since all taxes are levied for revenue. What else can taxation be called but the appropriation of funds from private individuals by the State for its own purposes? Some writers therefore amend the slogan to say: Taxation should be limited to revenue essential for social services. But what are social services?

We have thus analyzed all the alleged canons of tax justice. Our conclusions are twofold: (1) that economics cannot assume any principle of just taxation, and that no one has successfully established any such principles; and (2) that the neutral tax, which seems to many a valid ideal, turns out to be conceptually impossible to achieve. Economists must therefore abandon their futile quest for the just, or the neutral, tax.

(a) Equality before the law: tax exemption

Uniformity of treatment has been upheld as an ideal by almost all writers. This ideal is supposed to be implicit in the concept of “equality before the law,” which is best expressed in the phrase, “Like to be treated alike.” To most economists this ideal has seemed self-evident, and the only problems considered have been the practical ones of defining exactly when one person is “like” someone else (problems that, we shall see below, are insuperable).

(a) The ambiguity of the concept

Even the simplest maxims must not be taken for granted. Two centuries ago, Adam Smith laid down four canons of justice in taxation that economists have parroted ever since.60 One of them deals with the distribution of the burden of taxation, and this will be treated in detail below.

Up to this point, we have been discussing taxation as it is levied on any given individual or firm. Now we must turn to another aspect: the distribution of the burden of taxes among the people in the economy. Most of the search for “justice” in taxation has involved the problem of the “just distribution” of this burden.

Various proposed canons of justice will be discussed in this section, followed by analysis of the economic effects of tax distribution.

For centuries before the science of economics was developed, men searched for criteria of the “just price.” Of all the innumerable, almost infinite possibilities among the myriads of prices daily determined, what pattern should be considered as “just”? Gradually it came to be realized that there is no quantitative criterion of justice that can be objectively determined. Suppose that the price of eggs is 50¢ per dozen, what is the “just price”?