The metaphor of "stupid sheep" in Chapter 1 creates a juxtaposition between Siddhartha (a proudly independent man) and the rest of humanity (most of whom have a sheeplike tendency to follow others). In Chapter 1, Govinda uses this metaphor to compare Siddhartha to the rest of humanity:
Govinda knew that Siddhartha would become no ordinary Brahmin, no lazy sacrificial official, no grasping peddler of spells, no vain and empty orator, no evil, deceitful priest, and no good, stupid sheep in the herd of the many. No—nor did he, Govinda, wish to become any of those, a Brahmin like the other ten thousand.
The metaphor here is "stupid sheep in the herd of the many," which refers to people who refuse to think for themselves. Govinda decides to follow Siddhartha because he does not resemble a "stupid sheep"; he thinks for himself and has many positive leadership qualities. It is a bit ironic that Govinda respects Siddhartha for the very ability that Govinda himself lacks – Govinda could be considered one of the sheep he thinks of in this passage. He tends to follow people around and expects to discover the correct life philosophy through another person.
The insulting sheep metaphor creates a contrast between Siddhartha and other people (including Govinda). From the story's first pages, Siddhartha is an independent man willing to strike out on his own in a quest for enlightenment. He learns from many people along the way (such as Gautama, Kamala, and Vasudeva), but he never fixates on a single person or prioritizes their views above his own. He goes beyond the herd of humanity in search of his destiny.
In Chapter 1, Siddhartha contemplates the many wise sayings in the Upanishads, one of which contains a key metaphor about the soul:
True, many verses in the holy books, especially in the Upanishads of Sama-Veda, spoke about this innermost and ultimate—glorious verses. “Thy soul is the entire world,” they said[...]
The metaphor here is "thy soul is the entire world." One cannot understand it literally; rather, one must view it as a figurative expression of the soul's expansiveness. Siddhartha later discovers the truth of this saying after roaming the world in search of enlightenment only to find the key within his own soul. He feels empowered—yet isolated—by this concept. If one's soul comprises the entire world, then each person is a world unto themselves. The "innermost" equates to the "ultimate"; in other words, the soul contains everything a person might need to achieve the highest form of consciousness. During his journey, Siddhartha maintains an impressive degree of independence despite feeling lonely or isolated. His desire to excavate "the secret that is Siddhartha" takes immense effort and sacrifice. The metaphor of the soul as the entire world captures both the positive and negative aspects of seeking enlightenment: first, the knowledge of one's own power and self-completeness, and secondly, the potential loneliness that comes with self-sufficiency.
