Laughter

Why is Yitzchak named for laughter?  Why is Yitzchak able to open up the wells that Avraham had dug but the Phlishtim closed up?  Why is it ליצני הדור, as Rashi says, that deny Avraham's birth of Yitzchak?  Why are they called ליצנים?  Why is it that Yizchak is seen מצחק את רבקה אשתו?   

When Sarah sees Yishmael מצחק she says he has to go.  Similarly, after the sin of the agel the possuk says ויקמו לצחק.  Why are those acts of צחוק negative but the צחוק of Yitzchak is positive?  

What is the nature of צחוק?  The word צחוק can be split into צא חוק, to leave the natural order.  The middah of צחוק is to be able to go outside the boundaries of the normal order of things.  Entertainment, משחקים, is a way of escape.  It is a way of leaving the natural grind of life and escaping to a false existence.  The middah of צחוק can be negative when one leaves the order of morals, of a healthy way of life, and turns to sin.  When צחוק is positive it is used to bring a higher existence into the normal order.  This is the צחוק associated with Yitzchak.  This is a צחוק which only becomes ultimately realized at the end of the story.  

The middah of Yitzchak, of gevurah seems at odds with צחוק, it would seem the polar opposite?  But it is actually gevrah that leads to צחוק.  The wells of Avraham, the middah of chesed, are counterbalanced by the Pelishtim who are the embodiment of the tumah of chesed.  The Pelishtim are able to close up the influence of the positive chesed of Avraham with chesed of tumah.  The middah of Yitzchak, of gevurah, is to be able to bring out the capabilities from within a person and that was not able to be removed by the Phlishtim.  The ability to bring out dormant powers, to bring out kedusha from where it does not seem to be capable to exist is the middah of צחוק.  To be able to access kedusha where there would seem to be nothing there, to be able to access a higher level, is the middah of צחוק in the positive.    

The Sefer Yetzirah associates the middah of צחוק with Adar for Adar is the time when things seemed totally bleak.  Haman saw it as the month when Moshe Rabbenu died, it the last month of the year, a time which seems dead and bleak.  However, it is also the month of the birth of Moshe.  From the darkness ,unexpectedly, comes a time of great light and joy.  The opposite of what things seemed at first blush is the ultimate joke, the צחוק.   

This is why the life of Yitzchak is constantly being seen through the prism of צחוק.  The ליצנים don't want the power of laughter to be used for the positive, they wish to highjack it for the negative and could not accept that the legacy of Avraham would live on through Yitzchak.  Their claim was that Avraham's only son is Yishmael who is מצחק is a sinful matter.  That is the leztanut.  They wish to use this middah of צחוק not as a way of illuminating the world but as a way of darkening the world.  They claim that Yishmael has inherited the middah of צחוק and that they are not bound by Avraham's teachings of ethics and morals (based upon shiur of Rav Avraham Shwab, and "Looking Into The Sun" chapter on laughter, see also Tzitkas Hataddik #260.)