Comedy of Ideas
characters argue ideas or represent ideas (ie social class); The characters are more a representation of personalities, capable of change, pitting their wits (or lack thereof) against those who view reality differently. (ie Pygmalion)
Comedy of Manners
usually makes fun of aristocratic class; puns, paradoxes, epigrams, and witticisms
driven by the plot; characters are puppets of fate, plot is predictably improbable
At the bottom of the comedy ladder, man is almost indistinguishable from animal. The laughter is loudest over the dirty joke or gesture. This rung is for "bathroom humor" about body functions. This is very physical comedy with mishaps, loud collisions, and slapstick as well as physical exaggerations such as hairy warts, long noses, and humped backs.