10. A fuzzy inference apparatus comprising: an input device for entering input data related to phenomena; a storage device for storing knowledge of expert users expressing relationships between phenomena and conclusions as a plurality of membership functions, wherein said relationships include various multiple phenomena about which a single conclusion is to be drawn conjoined in an OR relationship and also include multiple phenomena and conclusions conjoined in an AND relationship; a grade calculating device for determining a grade measure for said input data with respect to each of said plurality of membership functions, for determining a first grade for a group of phenomena conjoined in an OR relationship, and for determining a second grade for another group of phenomena conjoined in an AND relationship; a fuzzy information amount calculating device for calculating the fuzzy information amount for each phenomenon using said grade measures; and a possibility calculating device for calculating the possibility of a conclusion using said grade measures, said first grade, said second grade and said fuzzy information amounts.
10. A fuzzy inference apparatus comprising: an input device for entering input data related to phenomena; a storage device for storing knowledge of expert users expressing relationships between phenomena and conclusions as a plurality of membership functions, wherein said relationships include various multiple phenomena about which a single conclusion is to be drawn conjoined in an OR relationship and also include multiple phenomena and conclusions conjoined in an AND relationship; a grade calculating device for determining a grade measure for said input data with respect to each of said plurality of membership functions, for determining a first grade for a group of phenomena conjoined in an OR relationship, and for determining a second grade for another group of phenomena conjoined in an AND relationship; a fuzzy information amount calculating device for calculating the fuzzy information amount for each phenomenon using said grade measures; and a possibility calculating device for calculating the possibility of a conclusion using said grade measures, said first grade, said second grade and said fuzzy information amounts. 11. The fuzzy inference apparatus of claim 10, wherein said grade calculating device determines said first grade for said group of phenomena conjoined in an OR relationship in a MAX calculation and determines said second grade for said group of phenomena conjoined in an AND relationship in a MIN calculation.