Is there just one possible world? Contingency vs the bootstrap

As an example of what might be considered a candidate for an interesting and significant development in the methodology of recent science, I examine some of the epistemological and ontological commitments of the bootstrap conjecture of high energy theoretical physics. This conjecture holds that a well defined but infinite set of self-consistency conditions determines uniquely the entities or paticles which can exist. That is, once we are given any partial information about the actually existing world, nothing else about that world is contingent or arbitrarily adjustable. This almost Leibnizian idea is implemented in S-matrix theory through a unitarity equation, which is a statement of conservation of probability. The S-matrix program is contrasted with quantum field theory which does have arbitrarily assignable quantities. In spite of the highly constrained structure of S-matrix theory, that theory makes far fewer ontological and epistemological assumptions than does quantum field theory.