Difference Between Man And Animal

In the Mir parsha sheet a couple of weeks ago, Rav Binyamin Cohen quoted from Rav Avrohom Schorr that the avodah of אני לדודי is to give one's אני, their own 'self' to Hashem.  By nullifying one's self before Hashem, then it will be ודודי לי.  The possuk Koheles (3:19) says ומותר האדם מן הבהמה אין.  According to this, we can translate as the advantage of a man over an animal is that a person has the ability to make themselves אין, to turn the אני into אין.