The Common Core Method and the Theory of Legal Formants

Sacco’s dissectioning the legal rule in a number of legal formants is the methodological step forward most useful for modern common core analysis.(from the Common Core website)

A discussion of the common core method in comparative law would be incomplete without mentioning the theory of legal formants that was introduced by Rodolfo Sacco.

Legal formants can be defined as all the elements that constitute the ‘living law’ of a country. They may vary in type and number from one country to another. Thus, it is probably impossible to compile a list of all legal formants that exist. Instead it is important to become aware of the three different kinds of perceptibility of legal formants. A part from the official sources of law, i.e. cases and legislation, other factors also influence how law is practiced in a particular country. Some of these other factors are more obvious, e.g. scholarly interpretation and judicial reasoning. Sometimes the elements of a legal phenomenon may only be partially obvious. Sacco calls the partially obvious legal formants synecdoche. In other cases, legal formants may be completely hidden. Sacco calls these hidden legal formants cryptotypes.

Cryptotypes (and to some extent probably also synecdoches) only become apparent when more than one system is examined through comparative study. Ideally the comparative lawyer, though privy to the legal systems discussed, is sufficiently detached as to abstract from the obvious rules in order to elicit implicit patterns and practices.

Three interesting contrasts are those between statute and the law as applied, the law as applied and the law as described, and between the situation the law deems to be normal and the situation that is normal in a sociological sense. (Sacco, infra, p. 378)

Through these implicit practices, rules that are prima facie contrary to each other, may indeed not differ from each other at all. It is the task of the comparative lawyer to discover such hidden commonalities among legal systems. And this, again, leads us back to the basic goal of the common core method in comparative law.


  • Rodolfo Sacco, Legal Formants: A Dynamic Approach to Comparative Law (Installment I of II), 39 Am. J. of Comp. L 1-34 (1991).
  • Rodolfo Sacco, Legal Formants: A Dynamic Approach to Comparative Law (Installment II of II), 39 Am. J. of Comp. L 343-401 (1991).

Is the Common Core Method a Variation of Functionalism?

Now that I have pointed out the singularity of the Cornell Project, I would like to make the connection with functionalism. (For an introduction to functionalism, see an earlier post.)

In a nutshell, functionalism starts on the premise that legal systems face similar problems for which they may take different measures yet in the end reach similar results. The common core method suggests that legal systems despite their prima facie diversity share a common core. So both methods are based on the idea that legal systems are not completely singular but have their commonalities. Continue reading Is the Common Core Method a Variation of Functionalism?

The Beginnings of the Common Core Method in Comparative Law

As I mentioned in my previous post, the Common Core Project is based on a method that was developed and first implemented in the 1960s by Rudolf Schlesinger. In 1957, Schlesinger published an article Research on the General Principles of Law Recognized by Civilized Nations in which he first presented his idea of finding out the common core of the legal systems of the world. He argued that the term general principles of law recognized by civilized nations (general principles) was relevant in many aspects of law ranging from international statutes (e.g. the statute of the International Court of Justice refers to the general principles) to court decisions (e.g. when it comes to the public policy doctrine). It was therefore important to find commonalities among the legal systems – a common core. Continue reading The Beginnings of the Common Core Method in Comparative Law