The tribal notion of “the common good” has served as the moral justification of most social systems—and of all tyrannies—in history. The degree of a society’s enslavement or freedom corresponded to the degree to which that tribal slogan was invoked or ignored.
“The common good” (or “the public interest”) is an undefined and undefinable concept: there is no such entity as “the tribe” or “the public”; the tribe (or the public or society) is only a number of individual men. Nothing can be good for the tribe as such; “good” and “value” pertain only to a living organism—to an individual living organism—not to a disembodied aggregate of relationships.
“The common good” is a meaningless concept, unless taken literally, in which case its only possible meaning is: the sum of the good of all the individual men involved. But in that case, the concept is meaningless as a moral criterion: it leaves open the question of what is the good of individual men and how does one determine it?
It is not, however, in its literal meaning that that concept is generally used. It is accepted precisely for its elastic, undefinable, mystical character which serves, not as a moral guide, but as an escape from morality. Since the good is not applicable to the disembodied, it becomes a moral blank check for those who attempt to embody it.
When “the common good” of a society is regarded as something apart from and superior to the individual good of its members, it means that the good of some men takes precedence over the good of others, with those others consigned to the status of sacrificial animals. It is tacitly assumed, in such cases, that “the common good” means “the good of the majority” as against the minority or the individual. Observe the significant fact that that assumption is tacit: even the most collectivized mentalities seem to sense the impossibility of justifying it morally.
But “the good of the majority,” too, is only a pretense and a delusion: since, in fact, the violation of an individual’s rights means the abrogation of all rights, it delivers the helpless majority into the power of any gang that proclaims itself to be “the voice of society” and proceeds to rule by means of physical force, until deposed by another gang employing the same means.
If one begins by defining the good of individual men,
one will accept as proper only a society in which
that good is achieved and achievable.
But if one begins by accepting “the common good” as an axiom and regarding individual good as its possible but not necessary consequence (not necessary in any particular case), one ends up with such a gruesome absurdity as Soviet Russia, a country professedly dedicated to “the common good,” where, with the exception of a minuscule clique of rulers, the entire population has existed in subhuman misery for over two generations.
Only on the basis of individual rights can any good—private or public—be defined and achieved. Only when each man is free to exist for his own sake—neither sacrificing others to himself nor being sacrificed to others—only then is every man free to work for the greatest good he can achieve for himself by his own choice and by his own effort. And the sum total of such individual efforts is the only kind of general, social good possible.
... from the Ayn Rand Column - Capitalism : The Unknown Ideal