The following two excerpts are taken from an article (VAN DIJK: Context and Cognition: Knowledge Frames and Speech Act Comprehension). In one place, the author writes:
This paper is intended as an introductory survey of some problems in the interdisciplinary domain of pragmatics and cognitive psychology. …I am indebted to Walter Kintsch for some helpful suggestions concerning this paper and for his permanent advice and collaboration in our work on discourse processing in general.
And in another, he writes:
As we will briefly mention below, conventions are involved, where conventions are taken as strictly objective properties of social structure.
How do you account for the difference in the use of person deictic expressions (I in the first part and we in the second), i.e. in the first the writer uses I, and in the second, he uses we?