In this paper, the author analyses learning as a function of the threshold between parties and ideas. Using Bakhtinian dialogic theory, literacy learning in particular is envisioned as a dialogue of the threshold. This instructional threshold is viewed both in pedagogical and biological terms. The physiological process of learning is described, making a biological case for instructional scaffolding and the gradual release of responsibility in the classroom. The dialogue of different disciplines serves as integration of several thresholds and further strengthening of learning. Curriculum integration is then promoted as a means to lasting learning.