Thesis (LLM)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The problem of mistake and its impact on the formation of contract is a central issue in the law of contract of all legal systems. The thesis investigates this area by considering the manner in which it has been dealt with in Germany and South African law. Although both legal systems are of the civilian origin. The German law is a codified system, whereas South African law is an uncodified one in which in the absence of legislation, legal problems are resolved by decisions of the High Court operating under a strict doctrine of legal precedent. German law does not in a formal sense acknowledge that judges can make law, but the thesis demonstrates the considerable weight that is nevertheless attached to judicial decisions in practice. The impact of differences in legal methodology on substantive law is a principal theme of the investigation. It is addressed by means of a systematic comparison between the manner in which the two systems deal with concepts such as heiuristic act and declarations of will, the notion of contract and the relevance of offer and acceptance as its constituent elements. Thereafter the broad topic of mistake as a circumstance that vitiates agreement and other defects of will such as deceit, duress and undue influence are considered. Whereas German law as a codified system presents a comprehensive regulation of the issues, a case law system such as that of South Africa can only deal with matters brought before the courts by parties engaged in a dispute. Because judges also tend to frame decisions as narrowly as possible, such a system characterised by gaps in the law in relations to issues that have not been authoritatively determined. The resultant uncertainty is exacerbated by the fact that different courts might decide the same issue differently and that a considerable period of time might elapse before the issue is settled by the highest court in the judicial hierarchy. In regard to matters of substance, both systems proceed from a common conceptual framework, but often tend to emphasise different aspects in coming to solutions. German law places great store on the notion of the declaration of will, a concept which is analysed in considerable detail in relation to its treatment in South African law. Although South African law recognises the notion of a juristic act, there is no sign of the refined and systematic discussion of the concept along the lines of German law. In consequence, concepts such as offer and acceptance play a less important role in South African law. In relation to the treatment of mistake as well the greater emphasis of German law on the declarations of will is in marked contrast to the more subjective approach of South African law and its resort to a theory of reliance as a corrective liability in cases of disagreement. Both systems adopt an approach with subjective and objective elements. but with a different mix of these elements in each instance. An overriding conclusion is that both systems might have erred in placing too great an emphasis on objective elements in the determination of when contractual liability should be imposed. It is contended that renewed attention to the doctrine of culpa in contrahendo might enable both South African and German law to deal more satisfactorily with the problem of disagreement in contract. / AFRIKAANSE OPSOMMING: Die probleem van dwaling en die uitwerking daarvan op kontraksluiting is 'n sentrale vraagstuk van die kontraktereg van alle lande. Die proefskrif ondersoek hierdie problematiek deur die hantering daarvan in sowel die Duitse as die Suid-Afrikaanse reg te oorweeg. Alhoewel beide hierdie stelsels van romanisriese oorsprong is, is die Duitse 'n gekodifiseerde en die Suid-Afrikaanse 'n ongekodifiseerde stelsel. In die afwesigheid van wetgewing, word regsprobleme in Suid-Afrika aan die hand van die gemenereg deur middel van beslissings van die hoë hof opgelos ingevolge 'n strenge presedentestelsel. Alhoewel die Duitse reg nie formeel erken dat regterlike beslissings regskeppend kan werk nie, toon die proefskrif aan dat daar tog in die praktyk groot gewig aan regterlike uitsprake geheg word. Die uitwerking van hierdie metodologiese verskille is 'n hooftema van die ondersoek. Dit geskied by wyse van 'n sistemariese vergelyking van die hantering in die twee stelsels van begrippe soos die regshandeling en die wilsverklaring. die kontrak en die rol van aanbod en aanname as konstituterende elemente van 'n kontrak. Hierna kom die breë vraagstuk van dwaling aan die orde as 'n omstandigheid war wilsooreenstemming ondermyn, asook die samehangende kwessies van bedrog, dwang en onbehoorlike beïnvloeding. Alhoewel beide stelsels in substantiewe aangeleenthede uitgaan van 'n gemeenskaplike konseptueie raamwerk. word aangetoon dat by die bereik van oplossings, die klem dikwels heel verskillend geplaas word. Van sentrale belang is vir die Duitse reg is die wilsverklaringsbegrip, wat in vergelyking met die behandeling daarvan. In Suid-Afrika in groot besonderhede ontleed word. Alhoewel die Suid-Afrikaanse reg, soos die Duitse reg uitgaan van die begrip regshandeling, ontbreek die genuanseerde en sistemariese behandeling van die Duitse reg. As gevolg hiervan speel die begrippe aanbod en aanname 'n relatief mlnder belangrike rol in die Suid-Afrikaanse reg. Met betrekking tot die dwalingsproblematiek ook is die groter klem op die Duitse reg op die wilsverklaring van die partye opvallend en in skerp teenstelling, tot die meer subjektiewe benadering van die Suid- Afrikaanse reg en die aanwending van die vertrouensteorie as 'n korrektiewe aanspreeklikheid in gevalle van 'n gebrek aan wilsooreesntemming. Alhoewel albei stelsels erkenning gee aan subjektiewe en objektiewe elemente, is daar verskille vir sover dit die relatiewe klem op elkeen aangaan. Die oorkoepelende gevolgtrekking is dat albei stelsels miskien te veel gewig gee aan die objektiewe element by die bepaling van aanspreeklikheid. Die voorstel is dat daar weer met vrug na die leerstuk van culpa in contrahendo gekyk sou kon word.