「はずだ」と「にちがいない」について

Abstract

This study analysed whether each meaning of hazuda and 　nichigainai　is confirmed by speaker or not. And, This study researched characteristics about the case that hazuda and nichigainai are possible or impossible to replace, and though the reason of the difference with related to the basic meaning of hazuda and nichigainai. The result is hazuda can be used at all of cases including things confirmed or not from the reality. hazuda expresses convinced and normative guess in case of no confirmation from reality. In the other hand, hazuda expresses speaker’s unexpected and satisfied emotions in case of confirmation from reality. Through the analysis of example sentences, hazuda shows unexpectation, satisfaction, normalization and conviction but this paper says the basic meaning of hazuda is normative and the other meanings are derivative. But, nichigainai is only used at the unconfirmed cases from the reality. Why nichigainai cannot be used at the confirmed cases from the reality is convictive meaning of nichigainai. That’s irony of guessing again that we already know the issues. And, at the unconfirmed cases from the reality, nichigainai expresses convictive guessing. But, when guessing the cause, nichigainai can be used only, and hazuda cannot be used. Because it is not adapted with natural meaning of hazuda. When we guess the cause of some events, it is possible to guess conviction but impossible to guess it is the natural cause. This study is that hazuda expresses natural judgment and nichigainai expresses convictive judgment. This two expresses can not be changed except the case of speaker’s guessing unconfirmed events at the reality. At this point, this study says that hazuda and nichigainai are positioned with different categories each other.