In this section, Freud considers the extent to which dreams are caused by physical events like "digestive disturbances" (5.4.1), aches and pains, or other sensations that our bodies experience in our waking and sleeping lives.
Freud begins by reminding his readers that, in Chapter 1, he discussed three different kinds of somatic (or bodily) sources that previous thinkers had debated: "objective sensory stimuli arising from external objects, internal states of excitation of the sense organs having only a subjective basis, and somatic stimuli derived from the interior of the body" (5.4.2).
Although Freud has already argued that dreams don't emerge from somatic sources alone, he now revisits some of his earlier points and adds a few additional comments.
Because Freud is willing to admit that some elements of dreams can emerge from somatic sources, he attempts to reconcile theories of the somatic sources of dreams with his own argument that dreams are wish-fulfillments. He does this by reiterating his point that dream-work "is under the necessity of combining into a unity all instigations to dreaming which are active simultaneously" (5.4.16).
In other words, Freud argues that although dreams are not determined by somatic sources alone, they may make use of somatic sources by incorporating them with the other dream-materials that have given rise to the dream.
"The essential nature of the dream is not altered by the fact of somatic material being added to its psychical sources," writes Freud. "A dream remains the fulfilment of a wish, no matter in what way the expression of that wish-fulfilment is determined by the currently active material" (5.4.17).
Freud states that because he is "an excellent sleeper" who "obstinately refuse[s] to allow anything to disturb [his] sleep," he is "very rarely" disturbed by "external causes of excitation" (5.4.18). In fact, he says that he can think of only one example in which "an objective and painful source of stimulus" was incorporated into one of his dreams (5.4.18).
In that dream, Freud was riding a horse. He writes that he rode "timidly and awkwardly to begin with," but soon "began to find myself sitting more and more firmly and comfortably on my highly intelligent horse, and noticed that I was feeling quite at home up there" (5.4.19).
In his interpretation of the dream, Freud explains that at the time, he had been suffering from painful boils that had popped up in certain, umm, sensitive areas of his body. These boils made it incredibly painful for Freud to sit or walk, and it would have been particularly excruciating for him to be bouncing up and down on a horse.
With this in mind, Freud argues that the dream fulfilled his wish to be rid of the painful boils. After all, if he was capable of riding comfortably on a horse, that must have meant that his private parts were boil- and blister-free.
As Freud goes on to note, though, his boils weren't the only source of the dream. The dream's contents included many other impressions, feelings, and wishes from his waking life, including feelings of professional annoyance and ambition.
Freud lists a few other dreams in which less pressing "external causes of excitation" made impacts on his unconscious. He also revisits some of the dreams that he has already discussed, and points out the specific dream-elements that seem to have been inspired by somatic sources such as pain, hunger, thirst, or a full bladder.
Freud now makes another small amendment to his theory of dreaming. He argues that "[a]ll dreams are in a sense dreams of convenience: they serve the purpose of prolonging sleep instead of waking up" (5.4.25).
In other words, "Dreams are the GUARDIANS of sleep and not its disturbers" (5.4.25).
From this premise, Freud infers that the "wish to sleep" is one of the primary motives for dreaming (5.4.26).
Freud continues to consider the roles that somatic stimuli play in dream-formation. He argues that "[w]hen external nervous stimuli and internal somatic stimuli are intense enough to force psychical attention to themselves, then—provided that their outcome is dreaming and not waking up—they serve as a fixed point for the formation of a dream, a nucleus in its material; a wish-fulfilment is then looked for that shall correspond to this nucleus" (5.4.27).
Freud uses this point to strengthen his position on anxiety dreams. He argues that painful or unpleasant somatic stimuli will likely be connected with wishes that have been suppressed—that is, wishes "whose fulfilment produces unpleasure" (5.4.27). In his view, this may be the cause of anxiety dreams (5.4.29).
Having returned to the topic of anxiety dreams, Freud offers an example from his own dream-life. He recounts a dream that begins like this:
"I was very incompletely dressed and was going upstairs from a flat on the ground floor to a higher storey. I was going up three steps at a time and was delighted at my agility. Suddenly I saw a maid-servant coming down the stairs—coming towards me, that is. I felt ashamed and tried to hurry, and at this point the feeling of being inhibited set in: I was glued to the steps and unable to budge from the spot" (5.4.34).
As Freud explains, this dream occurred after he had spent a day "trying to discover what might be the meaning of the feelings of being inhibited, of being glued to spot, of not being able to get something done, and so on" (5.4.33).
As he interprets the dream, Freud concludes that the feeling of being inhibited—of being "unable to budge from the spot"—had no counterpart in his physical experience while sleeping; instead, it related to the underlying sexual content of the dream.
Rather than explaining this point right away, Freud defers the discussion for the next section of the chapter, which will focus on "typical dreams."