(6a) Alan Jones: Do you want to join us for supper?
(6b) Lisa: No, thanks. I've eaten.
(6c) Lisa: No, thanks. I've already eaten supper.
(6d) Lisa: No, thanks. I've already eaten tonight.
(6e) Lisa: No, thanks. I've already eaten supper tonight.
All four answers communicate not only the same overall meaning but also the same explicature and implicatures. . . .
"Although all four answers in (6b)-(6e) convey the same explicature, there is a clear sense in which Lisa's meaning is least explicit in (6b) and most explicit in (6e), with (6c) and (6d) falling in between. These differences in degree of explicitness are analysable in terms of the relative proportions of decoding and inference involved: