Quote 1
"Decrepit families postulate decrepit wills, decrepit conduct." (35.61).
Angel blames Tess's past (i.e., her rape) on the fact that she comes from a "decrepit" family. Broken-down families create people with broken-down wills – people who can't think and act for themselves. So Angel seems to be coming down pretty firmly on the side of "free will" for the reason of Tess's rape, and he's putting an awful lot of the blame on the side of her "will," as opposed to Alec's. We all know that Tess's "will" and wishes weren't consulted at all by Alec, but Angel assumes that they were, and that she complied.
Quote 2
She was no longer the milkmaid, but a visionary essence of woman – a whole sex condensed into one typical form. (20.10)
In the early morning hours, Tess's beauty seems other-worldly to Angel. They're the only two people awake on the farm, and he can imagine that she's the only woman in the world. And so he condenses every thought and fantasy of what all women are or ever could be, and projects that ideal onto Tess. In other words, he's making her his ideal woman.
Quote 3
He called her Artemis, Demeter, and other fanciful names half teasingly, which she did not like because she could not understand them.
"Call me Tess," she would say askance; and he did. (20.10-11)
Angel thinks Tess is some kind of "Every Woman" – some ideal fantasy of femininity. So he calls her the names of Greek goddesses. But she doesn't like being generalized like that – she can't understand those names, and they detract from her unique individuality. She just wants to be called Tess, and understood for herself.
Quote 4
[…] he had asked himself why had he not judged Tess constructively rather than biographically, by the will rather than by the deed? (53.25)
Angel realizes his own injustice, and that the only real justice is in judging people by their intentions, rather than by their actions: "by the will rather than by the deed."
Quote 5
"[…] since you will probably have to leave at Christmas, it is in every way desirable and convenient that I should carry you off then as my property." (32.18)
It's surprising to realize that even a relatively good man like Angel Clare would buy into the idea that a wife is her husband's property.
Quote 6
"How can we live together while that man lives?" (36.82)
In other editions, Angel adds that Alec is Tess's husband in nature, if not legally. So again, there's a distinction between natural law and social law.
Quote 7
"Older than the centuries; older than the D'Urbervilles!" (58.30)
When Angel realizes that he and Tess have arrived at Stonehenge, he exclaims immediately about how old it is. It's older than the D'Urbervilles, and "older than the centuries." Older than time? Earlier in the novel, the ancient, "primaeval" forest of The Chase near Trantridge, and the May Dance tradition were our previous markers of the really, really ancient. Now, Stonehenge just blows them all away in the absolutely, time-out-of-mind, ancient-beyond-belief category.