In South Africa and elsewhere, the integration of science and Indigenous Knowledge Systems (IKS) is a contentious issue. This is due to both knowledge systems being underpinned by diverse epistemic authorities. This paper explores the possibilities and challenges associated with the integration of the two knowledge corpuses and how a Dialogical Argumentation Instruction (DAI) teaching approach could mitigate or aggravate such integration. A science class in a local school in Cape Town was exposed to a series of indigenous knowledge (IK) integrated science lessons for six weeks. The DAI approach comprised lessons structured after Toulmin's Argumentation Pattern (TAP) and with argumentation frames developed to categorize the learners argument responses. Individual, group and whole class activities examined various ways for processing indigenous foods through fermentation. Data sources involved classroom observations, written argumentation frame responses and one focus group interview. The Contiguity Argumentation Theory (CAT) has been used to capture and interrogate learners' arguments and experiences in mediating between science and IKS epistemologies beyond the scope of the logical deductive/inductive approach which TAP analysis employed. Analysis of learners' arguments revealed that they held both science and IKS worldviews and that they used them interchangeably without experiencing cognitive conflicts. The focus group interview showed that learners appreciated the inclusion of IK in the science lessons and felt that its inclusion can enhance their understanding of science. Discounting challenges faced, the DAI showed some promise, pending further investigations, that it could mediate the enactment of a science-IK curriculum.