may-at least partly -also be explained by this mechanism. Moreover, it is interesting to find out to what extent the adaptation process in legal rules follows the same principle as in biology. If the direction of adaptation were indeed toward simplicity in case of homogenisation of the environment, it would be an indication of the direction private law would take in a unified Europe (i.e. the environment of a highly uniform economy ) This biological idea is- the way I see it very much related to the famous race to the bottom argument. Unlike the present debate about that argument-that is merely on a normative level -evolutionary theory is able to show us that this process may be inevitable in a changing economic environment(section 5. 4). This argument may even be somewhat generalised with a view to the discussion on mentality as preventing a uniform European private law from coming about. 5.2 About the Way Private Law Rules Adapt to Changing Circumstances For the venture of creating a uniform private law for Europe, it is interesting to see what form this law is bound to take. Evolutionary theory predicts that the external identity of institutions may very well stay the same while their contents differs. This result is consistent with what legal history shows us: concepts like contract, tort, property and marriage may in name remain identical their content on the level of rules differs to a great extent over various periods of time. Thi combination of an"inherited"element and an element of variation guarantees that the adaptation of a rule to a new environment takes place in a not so overt way. To be more precise: a true elimination of one rule for another is not as likely as the adaptation of existing rules. Moreover, this adaptation or mutation of rules is not likely to happen in a stable evolutionary way. In biological evolution, the genes of a species are stable until there is a crisis(like an asteroid hitting the earth). It is only then that the species begins to mutate rather quickly and then either dies or adapts itself to the changed circumstances. The species may then be extremely good adapted for the period of crisis(having the characteristics to survive that crisis), but not for the period thereafter This theory can be substantiated with the following. The environment in which most of the present legal rules in Europe have survived, has been an environment of a national legal system that was most of the time embedded in a mixed market economy. Most of the private law les in continental Europe were able to survive because of their ability to adapt themselves to these characteristics. It is thus not much of a surprise that the surviving rules are the exponents of a liberal and individualistic model: in particular, they were extremely good adapted for the crisis of the French Revolution; these rules have subsequently been laid down in national civil codes Freedom of contract, the liability for damages in case of fault and the absoluteness of property including the rules originating from these concepts -thus have survived. To say that these concepts are well adapted for the present-day environment, is, however, hard to maintain. The many amendments that have been made to the rules emanating from these-indeed still under the same institutional heading- but in particular the importance that is attached to open ended norms (like good faith, reasonableness, negligence) in my view indicates that the present rules are now much less normative(and thus prescribing their future application) than they were at the time of the crisis they have survived Roe, supra note 48, at 6639 may – at least partly – also be explained by this mechanism. Moreover, it is interesting to find out to what extent the adaptation process in legal rules follows the same principle as in biology. If the direction of adaptation were indeed toward simplicity in case of homogenisation of the environment, it would be an indication of the direction private law would take in a unified Europe (i.e. the environment of a highly uniform economy). This biological idea is – the way I see it – very much related to the famous race to the bottom argument. Unlike the present debate about that argument – that is merely on a normative level – evolutionary theory is able to show us that this process may be inevitable in a changing economic environment (section 5.4). This argument may even be somewhat generalised with a view to the discussion on mentality as preventing a uniform European private law from coming about. 5.2 About the Way Private Law Rules Adapt to Changing Circumstances For the venture of creating a uniform private law for Europe, it is interesting to see what form this law is bound to take. Evolutionary theory predicts that the external identity of institutions may very well stay the same while their contents differs. This result is consistent with what legal history shows us: concepts like contract, tort, property and marriage may in name remain identical, their content on the level of rules differs to a great extent over various periods of time. This combination of an “inherited” element and an element of variation guarantees that the adaptation of a rule to a new environment takes place in a not so overt way. To be more precise: a true elimination of one rule for another is not as likely as the adaptation of existing rules. Moreover, this adaptation or mutation of rules is not likely to happen in a stable evolutionary way. In biological evolution, the genes of a species are stable until there is a crisis (like an asteroid hitting the earth). It is only then that the species begins to mutate rather quickly and then either dies or adapts itself to the changed circumstances.62 The species may then be extremely good adapted for the period of crisis (having the characteristics to survive that crisis), but not for the period thereafter. This theory can be substantiated with the following. The environment in which most of the present legal rules in Europe have survived, has been an environment of a national legal system that was most of the time embedded in a mixed market economy. Most of the private law rules in continental Europe were able to survive because of their ability to adapt themselves to these characteristics. It is thus not much of a surprise that the surviving rules are the exponents of a liberal and individualistic model: in particular, they were extremely good adapted for the “crisis” of the French Revolution; these rules have subsequently been laid down in national civil codes. Freedom of contract, the liability for damages in case of fault and the absoluteness of property – including the rules originating from these concepts – thus have survived. To say that these concepts are well adapted for the present-day environment, is, however, hard to maintain. The many amendments that have been made to the rules emanating from these – indeed still under the same institutional heading – but in particular the importance that is attached to open ended norms (like good faith, reasonableness, negligence) in my view indicates that the present rules are now much less normative (and thus prescribing their future application) than they were at the time of the crisis they have survived. 62 Roe, supra note 48, at 663