Sentence:  This circumstance in the patient 's case plus the fact that his tactual capacity remained basically in sound working order constitutes its exceptional value for the problem at hand since the evidence presented by the authors <WSD>is</WSD> overwhelming that , when the patient closed his eyes , he had absolutely no spatial ( that is , third-dimensional ) awareness whatsoever . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)