These subjects are discussed in the book, not in this article. This article is intended to shed light on the arguments given in the other chapters of the book. (2 he core issue of this article is the suitability of comparative concepts for comparat studies. The question of whether such comparative concepts are of any use has not been conclusively. In this article, I have attempted to synthesize some important points from of the literature. But first, some introductory remarks will be made in order to offer a framework Comparative concepts belong to the conceptual apparatus with which the comparatist can approach his discipline, a field which is not limited to only one legal system. Specifically, comparative concepts are concepts that are applied in micro-comparative research, ie. research carried out at the level of parts of legal systems. Correspondingly, comparative concepts are inadequate for dealing with legal families or with legal systems in their entirety. The proposition of this article is that comparative concepts enable us to compare legal rules belonging to different legal systems. Examples of comparative concepts are 'adoption and unjust enrichment, which refer to legal rules within different systems The premise of this article is that comparative concepts are criteria on the basis of which the rules of different legal systems may be compared. The legal rules to be compared must have the intension' of the comparative concept. This condition can be explained as follows: the intension includes the characteristics determining the applicability of the concept. The intension of the omparative concept is important since the intension must be explicit in order to make understandable which characteristics of legal rules account for their comparability 1. 2 The applicability of comparative concepts As stated above, comparative concepts are criteria on the basis of which the rules of different legal systems may be compared. This premise needs some further explanation Clusters of features are associated with terms like 'adoption' and unjust enrichment The comparatist will have to know which legal rules are the referents of these terms. The criteria of comparative concepts must be observable criteria enabling us to investigate empirically the rules belonging to different legal systems. However, the researcher preparing his investigation cannot be sure that the chosen concept includes observable criteria for its application. Results from other comparatists, if available, are not al ways sufficient to justify this conclusion. Therefore, in the first phase of comparative research, it is wise to assume only that legal rules are comparable Comparative concepts do not stand for innate notions which are present in the human mind, but for observable criteria The first phase of comparative research is of primary importance since observable criteria may prevent a waste of time in a later phase. The comparatist wants to study real referents of the comparative concept he has chosen as his starting point. Consequently, a hypothesis must be tested on the legal systems compared. I call a hypothesis containing a comparative concept the comparability assumption An example of such a comparability assumption is the following statement: because of the comparative concept of adoption, theThese subjects are discussed in the book, not in this article. This article is intended to shed light on the arguments given in the other chapters of the book.(2) The core issue of this article is the suitability of comparative concepts for comparative legal studies. The question of whether such comparative concepts are of any use has not been answered conclusively. In this article, I have attempted to synthesize some important points from of the literature. But first, some introductory remarks will be made in order to offer a framework. Comparative concepts belong to the conceptual apparatus with which the comparatist can approach his discipline, a field which is not limited to only one legal system. Specifically, comparative concepts are concepts that are applied in micro-comparative research, i.e. research carried out at the level of parts of legal systems. Correspondingly, comparative concepts are inadequate for dealing with legal families or with legal systems in their entirety. The proposition of this article is that comparative concepts enable us to compare legal rules belonging to different legal systems. Examples of comparative concepts are 'adoption' and 'unjust enrichment', which refer to legal rules within different systems. The premise of this article is that comparative concepts are criteria on the basis of which the rules of different legal systems may be compared. The legal rules to be compared must have the 'intension' of the comparative concept. This condition can be explained as follows: the intension includes the characteristics determining the applicability of the concept. The intension of the comparative concept is important since the intension must be explicit in order to make understandable which characteristics of legal rules account for their comparability. 1.2 The applicability of comparative concepts As stated above, comparative concepts are criteria on the basis of which the rules of different legal systems may be compared. This premise needs some further explanation. Clusters of features are associated with terms like 'adoption' and 'unjust enrichment'. The comparatist will have to know which legal rules are the referents of these terms. The criteria of comparative concepts must be observable criteria enabling us to investigate empirically the rules belonging to different legal systems. However, the researcher preparing his investigation cannot be sure that the chosen concept includes observable criteria for its application. Results from other comparatists, if available, are not always sufficient to justify this conclusion. Therefore, in the first phase of comparative research, it is wise to assume only that legal rules are comparable. Comparative concepts do not stand for innate notions which are present in the human mind, but for observable criteria. The first phase of comparative research is of primary importance since observable criteria may prevent a waste of time in a later phase. The comparatist wants to study real referents of the comparative concept he has chosen as his starting point. Consequently, a hypothesis must be tested on the legal systems compared. I call a hypothesis containing a comparative concept the 'comparability assumption'. An example of such a comparability assumption is the following statement: because of the comparative concept of 'adoption', the