1. An expert system for providing responses, actions or inquires in response to a set of conditions comprising: a set of goal variables representative of said responses and said actions; a set of variables representative of said conditions; a matrix of learning coefficients providing a matrix value for each combination of one from a set of resultant variables and one from a set of primary variables, said set of resultant variables at least including a set of goal variables representative of said responses and said actions and said set of primary variables at least including a set of varaibles representative of said conditions; an external interface for receiving said conditions to establish known primary variables and outputting said responses, actions or inquiries; and an inference engine including: means for computing likely values of said resultant variables from known primary variables in accordance with said matrix of learning coefficients, means for determining whether said likely value is a final determination, said likely value being a final determination when said likely value would be unchanged regardless of the value of the primary variables whose values are not known; means for determining a useful condition which will contribute to making a final determination of a resultant variable whose value has not been finally determined; and means for causing said external interface to output responses or actions in accordance with the finally determine values of said goal variables and to output an inquiry making for said useful condition.