The article is about identifying functional aspects of 1st-person statements with the explicit mode of ignorance (messages like I do not know… / We don’t know… I don’t know / We don’t know ...) in scientific discussions as a genre of scientific discourse. The relevance of the analysis is predetermined by the necessity to study various parameters of discourse (including both epistemic and pragmatic) as closely connected. The main research method is contextual and pragmalinguistic analysis. The sources of the material are transcripts of modern English and Russian scientific discussions in various fields of knowledge. The article identifies the illocutionary properties of ignorant statements, establishes their pragmatic functions, as well as determines their position in the traditional classification of speech acts. Taking into account the illocutionary orientation of references to ignorance makes it possible to identify representative, interrogative, axiological varieties of ignorance messages as well as their subtypes differentiated on the basis of the degree of their expressiveness, their vector of evaluation, the nature of the representative and interrogative role of speech acts with the mode of ignorance: fully expressive and conditionally expressive, positive and negative, preventive and hesitative, etc. The criterion “pragmatic functions” helps us specify additional functions of references to ignorance in scientific dialogue: to indicate a certain degree of the speaker’s epistemic responsibility for their words, to serve as a means of avoiding the answer, a way to prevent criticism, etc. Moreover, the work identifies factors determining the illocutionary nature of ignorance speech acts: the surface structure of the message, the general context of utterance, the position of the ignorance message in the dialogical unity, sincerity and felicity conditions of speech acts formulated as ignorance messages. References to ignorance are concluded to be quite a significant phenomenon in the structure of scientific dialogue, since they perform a number of important functions in it. The analysis scheme can be used to study statements with other explicit modes (knowledge, opinions, etc.) in various types of discourse.