Final answer:
The quote reflects Macbeth questioning reality and experiencing hallucinations due to the stress and guilt of his contemplated actions, illustrating his psychological turmoil and moral conflict.
Step-by-step explanation:
The quote "Or art thou but A dagger of the mind, a false creation, Proceeding from the heat-oppressed brain?" suggests that Macbeth is questioning reality and experiencing hallucinations. Macbeth, in his ambition to become king, is contemplating murder and is overwhelmed by the stress and guilt of his thoughts, causing him to see visions such as the imaginary dagger. This portrays the psychological turmoil and moral conflict that Macbeth is undergoing, providing insight into his disturbed state of mind as he considers the regicide that he soon commits.