| Quote #1
Jude went out, and, feeling more than ever his existence to be an undemanded one, he lay on his back on a heap of litter near the pig-sty. (1.2.39)
Much of Jude's feeling of isolation throughout the book simply stems from the fact that he feels like he has no place in the world. Well, that's probably a pretty popular cause for feelings of isolation across the board—we've certainly been there.
| Quote #2
Not a soul was visible on the hedgless highway […] the white road seemed to ascend and diminish till it joined the sky. (1.3.1)
Life in small town can be tough, and it can make you feel isolated. That's why there are so many books, movies, and Bruce Springsteen songs about trying to get out of a small town.
| Quote #3
Jude continued his walk homeward alone. (1.3.40)
Hardy does a really nice job of pointing out how often Jude is by himself throughout the novel. This is especially true in the opening chapter when Jude is growing up. Jude isn't great at forming strong friendships with other people, whether it's because his ambitions are too distant from those of the other people in Marygreen or because of some preference for isolation in his character.