why is the creature's appearance revevant? what does 'science' is shelley discrediting?

In Chapter 11, the monster searches for food, but when he finds a hut and enters it, his appearance causes an old man inside to shriek and run away in fear. He then proceeds to a village, where the sight of him causes even more people to run away. Because of these experiences, he resolves to stay away from humans.

In Chapter 12, he spends an inordinate amount of time admiring his neighbors and the way they look. After catching sight of his reflection in a pool of water, he retreats but continues to watch them. He even becomes somewhat attached to just being near them.

She has purposely disregarded psychology; it's a lesson for the reader.

Shelley is discrediting the science that dashes ahead without considering the possible outcomes and consequences. She is discrediting the whole venture of trying to play God. Victor creates the man not to have an offspring; he could easily do that the old fashioned way if he'd just go home and marry Elizabeth. No, he wants more than offspring; he wants an entire race to worship him as their creator. So, when the creature is ugly, rather than loving it anyway as any good father would, Victor runs away. He fails to parent this new being. In effect, Shelley is discrediting any science that brings people into the world without love and commitment.