VYGOTSKYS ZONE OF PROXIMAL DEVELOPMENT AND KRASHENS I- INCOMMENSURABLE CONSTRUCTS INCOMMENSURABLE THEORIES(1 )

Second language scholars, in public research and in public discussions , have suggested that Krashen's construct of i + 1 is similar to Vygot sky's zone of proximal development and that it might therefore be feas ible to integrate the two constructs in a way that would be productive for second language acquisition (SLA) research. After surveying publi cations relevant to the issue, we argue that this enterprise is futile , not only because the concepts are unrelatable, but also because they are rooted in incommensurable theoretical discourses. We also propose a way in which SLA research and theory might deal with incommensurabi lity.