the drug DES and in regard to German law a reference was even made to the Motive zu dem Entwurfe eines Burgerlichen Gesetzbuches fur das Deutsche Reich (12) It seems that in cases where the House of Lords is faced with a true dilemma, and the decision could go either way, not only traditional legal arguments, but also arguments based on comparative legal analysis are used. Especially relevant, so it seems, are decisions by foreign courts faced with the same dilemma. In the end, in Fairchild the House of lords overruled the decisions by the Court of Appeals and awarded the claims It is very interesting to see how the comparative legal arguments were used, which authority they have vis-a-vis traditional arguments based on an analysis of previous cases. The law lords first of all argue on the basis of a thorough examination of previous cases. At this stage, one can find aphorisms such as it has often been said that the legal concept of causation is not based on logic or philosophy. It is based on the practical way in which the ordinary man,'s mind works in everyday affairs of life. (13) The role of comparative legal analysis is seen as a'cross-check'. In the words of Lord Rodger of Earlsferry At the very least, the cross-check with these systems suggests that it is not necessarily the hallmark of a civilised and sophisticated legal system that it treats cases where strict proof of causation is impossible in exactly the same way as cases where such proof is possible. As I have tried to show, there are obvious policy reasons why, in certain cases at least, a different approach is preferable in English law too. The present are among such cases. (14) In other words, comparative legal analysis can only be a supporting, not a decisive argument Generally speaking, the House of Lords shows a desire to preserve the internal consistency of the English legal system. If, however, a problem arises, such as in this case, which could be decided either way, this desire to preserve internal consistency no longer is relevant. The court is in this, marginal, situation free to look for comparative legal arguments to support the final decision I hope to have made clear that convergence in tort law no longer is an abstract notion, or even an ideology, but has become a matter of legal practice. In the area of property law, based upon a first impression, the situation seems to be different However, underneath the historical differences between common law and civil law and hidden behind their wholly different legal techniques there is more common ground than one might think Property law Property law, as far as I can see, is considered to be a fairly complex system of highly technical legal rules in al most any legal system. In this area of the law, common law and civil law show fundamental differences in approach. This is for the most part due to historical developments. Onthe drug DES and in regard to German law a reference was even made to the Motive zu dem Entwurfe eines Bürgerlichen Gesetzbuches für das Deutsche Reich.(12) It seems that in cases where the House of Lords is faced with a true dilemma, and the decision could go either way, not only traditional legal arguments, but also arguments based on comparative legal analysis are used. Especially relevant, so it seems, are decisions by foreign courts faced with the same dilemma. In the end, in Fairchild the House of Lords overruled the decisions by the Court of Appeals and awarded the claims. It is very interesting to see how the comparative legal arguments were used, which authority they have vis-à-vis traditional arguments based on an analysis of previous cases. The law lords first of all argue on the basis of a thorough examination of previous cases. At this stage, one can find aphorisms such as: . . . it has often been said that the legal concept of causation is not based on logic or philosophy. It is based on the practical way in which the ordinary man's mind works in everyday affairs of life.(13) The role of comparative legal analysis is seen as a 'cross-check'. In the words of Lord Rodger of Earlsferry: At the very least, the cross-check with these systems suggests that it is not necessarily the hallmark of a civilised and sophisticated legal system that it treats cases where strict proof of causation is impossible in exactly the same way as cases where such proof is possible. As I have tried to show, there are obvious policy reasons why, in certain cases at least, a different approach is preferable in English law too. The present are among such cases.(14) In other words, comparative legal analysis can only be a supporting, not a decisive argument. Generally speaking, the House of Lords shows a desire to preserve the internal consistency of the English legal system. If, however, a problem arises, such as in this case, which could be decided either way, this desire to preserve internal consistency no longer is relevant. The court is in this, marginal, situation free to look for comparative legal arguments to support the final decision. I hope to have made clear that convergence in tort law no longer is an abstract notion, or even an ideology, but has become a matter of legal practice. In the area of property law, based upon a first impression, the situation seems to be different. However, underneath the historical differences between common law and civil law and hidden behind their wholly different legal techniques there is more common ground than one might think. III Property law Property law, as far as I can see, is considered to be a fairly complex system of highly technical legal rules in almost any legal system. In this area of the law, common law and civil law show fundamental differences in approach. This is for the most part due to historical developments. On