Modern science and technology vs superstition
Stoker's England is a land in love with modern science and technology. Seward keeps his diary on a phonograph; Mina has her typewriter. Seward is a devotee of the scientific method: he observes both Lucy and Renfield as they come under the spell of the Count and keeps careful notes. Mina is another keen note-taker, writing all that happens in her diary. But both Seward and Mina are blind to the cause of Lucy's decline. Their rational prejudices prevent them from understanding what is happening under their noses. Jonathan Harker is another victim of the narrow scientific mindset. He cannot make any sense of his experiences in Transylvania, mistakenly consigning them to the world of dreams or imagination. Like old Mr Swales, these people have turned their backs on old beliefs and superstitions. But this is exactly the element in which the Count exists and moves. His Transylvania is a world where peasants devoutly pray in roadside shrines and use charms against vampires and the evil eye. The Western European men's blindness to the reality represented by the Count makes them vulnerable to his attacks.
Dracula is a cautionary tale against rejecting out of hand the old knowledge and beliefs. Van Helsing is able to understand the Count's machinations because he is a master of the old knowledge as well as the new. He uses folk remedies such as garlic and Christian paraphernalia such as crucifixes to fight the Count - all aspects of belief and tradition which have been dismissed as irrelevant by the modern young men and women of the novel.
Van Helsing uses Christian symbolic objects like crucifixes and Communion wafers to control and defeat the Count and his fellow vampires. They have a seemingly magical power over vampires, to such an extent that at times, the novel reads like crude Christian propaganda. Van Helsing describes the band of friends who oppose the Count as "ministers of God's own wish," on a kind of holy crusade. The souls of the vampire Lucy and the Count are damned as long as they are actively Un-dead, but after Van Helsing's band destroys them with stakes through their hearts, their souls are redeemed in spite of all the sins they have committed. Lucy's face shows a "holy calm" and her soul "is with Him" (God); the Count's face shows "a look of peace, such as [Mina] could never have imagined might have rested there."
Christianity had provided the beliefs that underlay the moral code of society for hundreds of years, but, along with old superstitions and folk remedies, it was being rejected in Stoker's day in favor of a faith in science and technology. This was underscored by the rising popularity of Charles Darwin's The Origin of Species (1859), which challenged the old idea that man was created by God in His own image and put forward the theory that man evolved from an ape-like ancestor, and that, far from being divinely ordained to rule the earth, he was just another species in the chain. In Dracula, Stoker shows a society on the edge of moral collapse and implicitly warns against the wholesale rejection of Christian values.
Altered states of consciousness
The Count represents an alternative reality to the reason- and economics-based world of modern London, and that reality can only be accessed by a consciousness that is not restricted to the rational faculty. Altered states of consciousness are common in the novel, and it is these states that provide a window through which it is possible to access the alternative reality of vampires. They include insanity (Renfield's usual state, and Harker's temporary state during his nervous breakdown); sleepwalking (Lucy); hypnotic trance (Mina); and dreams (Mina, Lucy and Harker). These are also the states in which, according to psychoanalytic theory, people can access the unconscious, the realm where the disallowed and suppressed elements of the psyche are stored. The more aspects of the psyche are suppressed, the more they will demand expression via the unconscious, which is why Harker and Lucy have such demanding unconscious minds - Harker in his nervous breakdown, Lucy in her sleepwalking.
While the band of friends who oppose the Count are restricted by their excessive reliance on the rational, conscious mind, they are guided by Van Helsing, who is master of both the rational world of science and the alternative world of the occult and supernatural. One way in which Van Helsing accesses the Count's world is by hypnotizing Mina. Hypnosis is a scientific route to the unconscious. In her semi-vampire state, Mina can temporarily access both worlds.
Dracula is usually seen as a novel about suppressed sexuality, especially female sexuality, for which vampirism is a metaphor. Four of the five women characters are vampires, and their sexual aggressiveness and insatiability are presented as men's secret fantasy and greatest nightmare. Lucy's transformation from respectable Victorian lady to voracious sexual predator is a cautionary tale warning us of the threat that the Count, through his sexual prowess, presents to civilized society. Such women prey upon innocent children (Lucy and the vampire women both do this) and seduce and drain men, driving them from their reason through their power of arousing sexual desire. Sexuality is only safe when it is monogamous, low-key and sanctified by the production of children within marriage, as represented by Mina before her corruption by the Count and after she is 'cured' of vampirism by his destruction. It is remarkable that Harker has far more sexual interaction with the vampire women in one short scene than with his wife in the entire novel.