  We study the exact renormalization group of the four dimensional phi4 theory
perturbatively. We reformulate the differential renormalization group equations
as integral equations that define the continuum limit of the theory directly
with no need for a bare theory. We show how the self-consistency of the
integral equations leads to the determination of the interaction vertices in
the continuum limit. The inductive proof of the existence of a solution to the
integral equations amounts to a proof of perturbative renormalizability, and it
consists of nothing more than counting the scale dimensions of the interaction
vertices. Universality is discussed within a context of the exact
renormalization group.
