Q. Is Tashlich on Rosh HaShanah afternoon really necessary?A. Tashlich is the symbolic casting off of sins in a body of water.
Some rabbis strenuously objected to the practice on the basis that it deflects you from the spiritual tasks of penitence, prayer and charity.
Others disliked the symbolism of transferring your sins elsewhere without necessarily showing that you repent for your misdeeds and are determined not to do them again.
In favour of the practice it should be recognised that “casting off one’s sins”, based on a verse about God casting our sins into the depths of the sea” (Micah 7:19), is metaphorical, a poetic way of saying, “I regret my sins so profoundly that I pray that God may remove any trace of them so that I may begin the new year with a clear conscience”.
A similar thing could be said about the section of the Yom Kippur Musaf liturgy that describes the removal of human sins by means of the scapegoat that was sent into the wilderness.