¶1*433ORDER ON PETITION FOR REHEARING
¶2In her petition for rehearing the Respondent, Carol Rutherford, raises the issue of whether this court has unfairly discriminated against the mentally ill as a class by requiring her to establish her defense to adultery by “clear evidence,” a higher standard of proof than the usual standard of preponderance of the evidence. There may be merit to such an argument. We therefore modify our opinion to require Respondent, Carol Rutherford, to prove that her mental condition deprived her of the ability to control her various personalities by a preponderance of the evidence. We hold, however, that she did not meet that burden of proof.
¶3Respondent, Carol Rutherford, also argues in her petition for rehearing that our standard of review of family court issues is restricted by S.C. Code Ann. Section 14-3-320 (Supp. 1990) to a consideration of whether there is “substantial evidence” to support the family court’s findings. We disagree.
¶4A divorce proceeding is a proceeding in equity. Roberts v. Roberts, 299 S.C. 315, 384 S.E. (2d) 719 (1989). Article V, Section 5 of the South Carolina Constitution provides “the [Supreme] Court shall have appellate jurisdiction only in cases of equity, and in such appeals they shall review the findings of fact as well as the law____” This same standard applies to this court since we derive our jurisdiction by transfer from the Supreme Court pursuant to S.C. Code Ann. Section 14-8-260 (Supp. 1990).
¶5Our Supreme Court has consistently interpreted the constitutional language quoted above to mean that in equity cases it may decide fact issues based upon a preponderance of the evidence. Miller v. Miller, 299 S.C. 307, 384 S.E. (2d) 715 (1989); Gilbert v. McLeod Infirmary, 219 S.C. 174, 64 S.E. (2d) 524 (1951); Young v. Levy, 206 S.C. 1, 32 S.E. (2d) 889 (1945). It is settled law that where a statute is repugnant to the constitution, it cannot prevail. University of South Carolina v. Mehlman, 245 S.C. 180, 139 S.E. (2d) 771 (1964); Southeastern Home Building & Refurbishing v. Platt, 283 S.C. 602, 325 S.E. (2d) 328 (1985). To the extent Section 14-3-320 is repugnant to Article V, Section 5 of the South Carolina Constitution, the statute is void.
¶6We have carefully reviewed the remaining bases for Mrs. Rutherford’s petition for rehearing and find them to be without merit. Her petition for rehearing is therefore denied.
¶7The South Carolina Protection and Advocacy System for the Handicapped, Inc. and the Mental Health Association of South Carolina have petitioned for leave to file an amicus curiae petition in support of Mrs. Rutherford’s petition for rehearing. This court grants that petition, has considered the petition, but finds it unpersuasive except to the extent it relates to the modifications we have made to our opinion.