Tazria-Metzorah

In this weeks parasha, the Torah discusses the nature and consequences of Tzara’at. Often translated as biblical leprosy  (although this is too simplistic a translation and it would be incorrect to associate it with modern leprosy) - it was  a condition that could only be diagnosed by a Cohen/Priest and consequence of a diagnosis could be a period of exile from the camp.

I have always been fascinated by the requirement of exile as part of the ‘recovery’ process for Tzara’at. Why should this disease mandate such a reaction? Why do we force out the one who is suffering? One approach in the commentaries is that this is an early example of public health policy. Both Rabenu Bachaye (1255-1340) and the Meshech Hochma (1843–1926), suggest that Tzara’at was a highly infectious disease, and therefore those who were infected needed to be placed in a form of quarantine to protect the health of the population. Once they were no longer infectious they could safely be re-integrated into society.

However, such an approach is not the norm and many commentators follow the approach of the Babylonian Talmud viewing Tzara’at as the physical manifestation of a spiritual ailment (hence the requirement to be diagnosed by a priest). In Tractate Arachin 16a, Rav Yonatan associates Tzara’at with a whole range of sins ranging from slander/damaging speech to murder. Accordingly, it becomes clear that the period of exile was supposed to encourage the afflicted to reflect on their behaviour and undergo a process of rehabilitation which would then enable them to re-enter society fully reformed.

With respect to the previous two interpretations, I would like to venture a third one which melds the previous two together. In the last few years, a number of longitudinal studies have been published looking at how behaviour spreads across social networks (the old fashioned kind- i.e. groups of friends/colleagues). In these studies, which monitored social networks for a period of up to 25 years, behaviour has been shown to be contagious. For example, results from a set of studies by Nicholas Christakis and James Fowler (see publications from 2007 & 2008) reported on individuals who were followed for over 30 years. They found that one was 57% more likely to become obese if a friend became obese. Similarly (and more positively) they found one was 37% more likely to quit smoking if a friend quit smoking. The headline that can be taken from these studies is that behaviour is contagious and can be thought of as a communicable disease. If we follow the opinion that Tzara’at was a punishment for errant behaviour, it makes sense that the individual should be exiled, not only to enable them reflect on their behaviour, but just as importantly, to prevent their behaviour from ‘being caught’ and being taken up by other members of their social network. Maybe, exile for Tzara’at was to protect society from spread of negative behaviours.

In this era where biblical Tzara'at is non-existent, maybe we can use this weeks Torah portion to reflect on the nature of influence. As the studies demonstrate, a by product of living in a social society is that our behaviours are catchy. If we choose to act  in a certain manner, it is likely that we will exert influence on others to behave a in a similar way.   Behaviour is contagious, so lets choose to behave in a way that is positive and benefits society, and lets influence the world around