Breaking with the Past 241ternal authority but rather by its own intrinsic nature. Th ere are legal limita-
tions, then, on state action; but they are self- imposed.
Th e autolimitation concept was potentially a very fertile one. It could ex-
plain, for example, the key principle of pacta sunt servanda— and thereby
account for the whole of treaty law. States appreciate the value of stability in
their relations with one another, and each state readily perceives, on its own,
that a general rule requiring adherence to treaties is to its own real advan-
tage. In other words, each state in de pen dently adopts the principle of pacta
sunt servanda as a guiding rule for itself.
Th e voluntarist version of positivism, and the autolimitation thesis spe-
cifi cally, came to be associated with neo- Kantian modes of thought. Th e es-
sence of the neo- Kantian picture of international law was Kant’s opinion
that the essential task of law is to coordinate the in de pen dent wills of the
actors in a system, with a view to maximizing both individual freedom of
action and due respect for the rights of fellow actors, in some kind of combi-
nation. It is an application of Kant’s original conception of a po liti cal soci-
ety as “a relationship among free men” who “retain their freedom within the
general union with their fellows.” Th e aim of international law is not to
coerce states from, as it were, outside or above, but instead “to preserve and
secure the freedom of each state in itself, along with that of the other...
states.” Kant characterized this idea as a vision of a “free federation.”
Kant’s alternative to the Hobbesian world of anarchy and perpetual con-
fl ict was not to institute a sovereign, but instead to devise a system in which
all of the agents would be left with their freedom— but would exercise that
freedom in a spirit of self- restraint and mutual respect. Th e neo- Kantian
solution was broadly in this spirit. What it added to Kant’s original analysis
were the concepts of the Rechtsstaat and autolimitation. Th ese were the
means by which the necessary ethos of self- restraint would be infused into
international aff airs. Th e most important value underpinning the system—
and the ultimate source of international order— was a shared ethic of reci-
procity. No state can claim anything for itself that it would refuse to concede
to another.
It is readily apparent that neo- Kantianism is an optimist’s charter, directly
refl ecting Kant’s confi dence that “a respect for the concept of right” is an in-
herent and ineradicable feature of human beings. Th e neo- Kantian interna-
tional lawyers held much the same opinion, in the form of their concept of