Eiruvin 93a, b

The rabbis continue their conversation about adjoining or attached courtyards.  Today they consider the possibility of a courtyard that ends at an embankment.  How tall would the partition have to be when rising up or reaching down to its adjacent courtyard?  Generally speaking, a partition must be 10 handbreadths high.  The rabbis eventually agree that a five handbreadth embankment (or natural partition) would only require five additional handbreadths of partition.

This conversation shifts into the halacha regarding the mixing of crops. Often discussions of eiruvin collide with conversations regarding crops, as the laws have some similarities.  The rabbis discuss how partitions might work when separating one courtyard used for 'growing' from another.  How many cubits of unsown land are required to separate one crop from another?  What if one wished to grow a crop within another crop -- how much distance is necessary for the crops to be permitted?  Because the prohibition of mixing crops is a Torah law, the rabbis are more stringent regarding its interpretation.  With eiruvin, which are based on rabbinic law, leniencies are allowed and encouraged quite frequently.

At the end of the daf, the rabbis discuss implications of changes occurring on or before Shabbat.  This questions arises often in Eiruvin.  "If all is kosher (regarding eiruvin and permission to carry) before Shabbat but then becomes not-kosher during Shabbat, are we allowed to continue carrying across domains?"  and "If something becomes not-kosher just moments before erev Shabbat, are we allowed to begin carrying across domains?"  The rabbis are thoughtful about these circumstances, and efforts seem to be made toward leniency.

This overview of today's daf is a gross simplification of the rabbis' discussions.  I have found myself bogged down with the intricacies of eiruvin, and I am working toward grasping just the basic tenants.  I am unclear as to why the rabbis continue with these conversations at this point in eiruvin.  Over the past two dapim, I wondered whether we were beginning to trend toward more inclusive eiruvin, similar to those used today.  I could be wrong, but I do not believe that it is necessary to create many different eiruvin for different 'courtyards' in modern times.  Again, I may be wrong.  I had hoped that I would be reading more about collective efforts to create eiruvin across adjacent courtyards, cities, fields... well, not today.