Can AI Argue More Sufficiently and Tactfully?

Although AI-generated texts are increasingly attractive to the EFL/ESL researchers and teachers, few studies have examined those texts from logical and rhetorical perspectives. This study explored whether AI model can argue more sufficiently and tactfully than human writers. The data source consisted of 60 argumentative essays from EFL learners’ written corpus and a parallel ChatGPT-written corpus. Content analysis and quantitative analysis were employed to do the comparisons. The results displayed that the ChatGPT could argue more sufficiently than the EFL students by providing more grounds and warrants to justify the claims, and that it could only use monotonous type of warrant to gain argument sufficiency despite its same preference of argument width as the human writers, that is, using parallel arguments to support the claims. Moreover, the machine showed less tactfulness by expressing claims with more certainty and by using fewer concessions before refuting. Implications in writing instruction are emphasized such as the culturally and emotionally embedded nature of human communication.