In recent decades, important advances have been made in understanding how discursive symmetry can be achieved in whole-class dialogue. However, very little is known about how this dialogue may progress in the sense of critically linking ideas in coherent lines of collective inquiry. This article investigates this issue by analyzing 4 consecutive sessions of a science class with children ages 8 to 10 and identifies a social mechanism that can explain the emergence of progressiveness in collective inquiry. The identified mechanism consists of a series of iterations of the sequence (Direction) [right arrow] Inference [left-right arrow] Observation [left-right arrow] Consensus [right arrow] Fixation. This sequence enables the transition from local to collective agency and meaning. Direction creates a gap in a semantic structure, leading to the local formation of an inference. This inference then escalates through observation and consensus before finally being fixed through the creation of an artifact that reifies it as a collective meaning. Based on this collective meaning, a new direction leads to a new local inference, and the cycle begins again.