Does the reasonable doubt standard apply to the privilege against self-incrimination contained in section 15 of the state Constitution?

Although the defendant urges that the privilege against self-incrimination contained in article I, section 15 of the state Constitution requires application of the reasonable doubt standard in order to fully protect the important values embodied therein, we find it unnecessary to reach the constitutional question as we conclude for the reasons set forth below that the reasonable doubt standard is required as a judicially declared rule of criminal procedure. (See People v. Gainer (1977) 19 Cal.3d 835, 852, 139 Cal.Rptr. 861, 566 P.2d 997 and cases cited therein.)