Realism, with regard to literature, is a relative term. Thomas Hardy's novels, in my view, exemplify realism more fully than other English writers of his time and earlier, but less than a contemporary such as Emile Zola. Tess of the D'Urbervilles, though it's reasonably frank in its subject matter, is still reticent (compared not only to Zola but other writers such as Tolstoy) about sexual matters to the point where, for example, we are never told directly that Tess's encounter with Alec is, to put it mildly, non-consensual. That said, the fact that Hardy deals with pregnancy and single motherhood at all, and the issue of sexual double standards between men and women, is a huge step forward in realism for English and American writers of the time. Tess and her family are simple country people. Realism, and the more intense form of it labeled naturalism, typically focus upon people of limited circumstances and their misfortunes. Often their exploitation by the rich and the stark difference between poor and wealthy people are among the themes of realistic fiction. Abandonment, isolation, loneliness, and finally, violence and killing, are explored with a (relative) lack of frills or sugar-coating by Hardy as he narrates Tess's tragic story.

Realism also tends to see the universe operating according to a kind of randomness, without justice for the poor or the innocent. In Tess, events upon which the plot turns often occur by accident, rather than being driven by deliberate effort, either through human or divine force. Tess herself is a victim of this type of chance happening, as in, for instance, her failure to inform Angel of her "past" before their marriage. It is debatable whether Hardy is making a direct point about the unfairness of the system to women or is just reporting this as a fact of life, but in either case the fact that he shows the unfortunate consequences for Tess is an example of the overall realism that informs the novel.

Tess is often referred to as a naturalist novel because it shows nature and God, if there even is one in Hardy's universe, as indifferent to human fate. But it is also a realistic novel. Aspects of realism include the fast fading of the ancient folk culture of the Wessex region depicted in the novel's opening. The novel also shows the way life-holds—farm leases that lasted only a few generations—were being snatched away from small farmers, leaving them in precarious economic positions.

When Tess works at the dairy, it is an idealized spot but at the same time realistically depicted as a working farm—it is no pastoral fantasyland where the milkmaids dance about in silk dresses and the fruit falls without labor off the trees. Tess and her fellow workers really work, getting up before dawn to milk the cows and painstakingly picking the wrong kind of grass out of the pastures so the cows aren't harmed. What Hardy shows is a hard but good life where the workers live in simple abundance because they are under no middle class pressure to put on airs or a show.

Another realistic note is the narrator's comment that had Tess simply applied to Angel's family for relief, they would have offered it, for they were not unkind people. Hardy does not want to turn middle class people as a whole into a caricature of hypocrisy but simply to show the damage the sexual double standard could cause.

Finally, when Alec says that people like he and Tess, who do not have the protections offered to higher class people, pay to the uttermost farthing for their transgressions, he is only stating the reality of social life in Victorian England.

Realism is established in Hardy's Tess of the d'Ubervilles each time she is taken out of her fanciful, dream-filled mind and forced to look life in the face when a real-world experience consumes her. For example, Tess first goes to Alec d'Uberville's at the request of her mother and possibly to marry him. After she gets to know him, however, she doesn't like him and doesn't want to marry him. The reality of the conflict between rational thought and physical desires confronts Tess when she falls into a passionate affair with Alec that results in her becoming pregnant. With each choice that Tess makes, a real consequence seems to surprise her afterwards--such as the time when she decides to leave Alec and head back home to her mother. She seeks refuge at home rather than marry the father of her child. As a result, she is faced with the whispers of a pious community who can only see her sins and not her plight. This is a reality that faces young mothers today just as it did back in Hardy's time. Even though we might think he or she can handle life, the results of choices tend to surprise us. Tess faces other bouts with reality after her baby dies, after she marries Angel, and after she kills Alec. It's as if she can't think farther ahead about the consequences that might come from the choices she makes and she ends up suffering for them.