Final answer:
The irrational element in the soul, as per Aristotle's philosophical inquiry, influences actions and emotions that aren't governed by rational thought. This component is present across various species but manifests differently depending on the type of soul, with the collective unconscious playing a critical role in shared psychological tendencies.
Step-by-step explanation:
One irrational element in the soul common to all species is responsible for actions that arise from the part of the soul which operates beyond rational thought. According to Aristotle in his work On the Soul, all living beings possess different types of souls which allow for various capacities. For plants, the soul promotes growth and exchange of nutrients. The animal soul adds to these capacities the ability to desire and to move. In humans, the rational soul rises above these functions, giving humans the unique capability for higher reasoning, critical thought, and self-reflection. Engaging in rational thought is essential for understanding why we do what we do and for self-examination. However, the irrational elements contribute to impulsive actions, emotions, and instincts, which, although they may at times lead to actions that are tough to rationalize, are a fundamental part of the shared animal nature and upper cognitive functions that include the collective unconscious described by Carl Jung.