Knowing that Kafka was a German speaking Jew born in Prague - then part of the Austro-Hungarian Empire gave me the idea that perhaps the transformation of Gregor Samsa was an illustration of Kafka's sense of his difference from non-Jews at the time. To be a Jew during the time of WWI was to feel the wrath of society because Jews were to blame for every political, social and economic problem.  His difference is something about which nothing can be done.  He feels guilt, aloneness, alienation from others.  It is arbitrary how one is formed and into what kind of family one finds oneself.  There is no explanation why Gregor deserved such a fate and it's acceptance is something seen as quite natural.  He nor his family sought medical help or any other.  They all just accepted this horrible insect as their son/brother without bothering to find a remedy.  Interestingly Gregor soon finds himself more comfortable cramped up under his bed in a tight dark space.  He is hiding out from abuse.  He withdraws completely from society because he feels hopeless and has no connection to anyone. Even his sister who cared for him at the beginning is repelled by him now and wants him out of the way.  Gregor's physical life shapes and directs his mental life, just as the wounded soldier Jake Barnes' physical injury impacted his mental state and how he related to women especially.  The physical body cannot ignore what constrains it even if it tries mentally.The metamorphosis of a man into a spider- like monster is an extension of the alienation Gregor already felt as a person.