Gilbert Harman has posted a revised version of his earlier remarks, along with a reply by Marc Hauser.   It seems to me that "theft of ideas" clearly constitutes plagiarism and academic dishonesty (see the discussion in Harman's piece on this subject), though many egregious cases go unpunished and unnoted because the ideas in question were only in oral form prior to the theft.  But that is not the case in this instance.   In any case, see the detailed analysis by Harman and the rejoinder from Hauser.