In literary discussions, "romantic" generally highlights the importance of imagination and sensory experiences over logic and reason. In the context of pre-Civil War America, romanticism and transcendentalism have more distinct associations, both of which are explored further in the historical context section below. In “When I Heard the Learn’d Astronomer,” Whitman draws on a specific form of romanticism and transcendentalism, evident in the poem's contrast between the value of sensory imagination and the logical scientific method used to comprehend nature.

The poem's opening quatrain emphasizes the mathematical logic of the scientific process, illustrating how data from the natural world is systematically organized. Although the astronomer's skill in organizing information is noteworthy, Whitman’s language suggests this scientific approach is confined to a lecture hall, detached from the celestial wonders themselves. Whitman implies that the speaker feels “tired and sick” because manipulating data and sitting in an applauding lecture room is less fulfilling than quietly observing the stars. The richer language and imagery in the poem's final three lines indicate a preference for romantic mysticism over scientific logic.

However, this does not necessarily imply that the speaker is uninterested in astronomy or that the scientific process lacks value. Whitman, who personally had an interest in astronomy and the scientific advancements of his era, hints in line 6 that the speaker is somewhat aimless upon leaving the lecture hall, using the word “wander’d.” Therefore, wandering and mysticism are not necessarily Whitman's definitive alternatives to the structured logic of the lecture room. It's possible the “unaccountable” speaker is simply grappling with the precision and truths of science. Nonetheless, the poem suggests that logic and science often fall short in capturing the broader understanding of the world that a romantic perspective can provide.

Walt Whitman's concept of "Personalism" presents a distinctive perspective on individualism. It encourages people to live freely while recognizing the democratic principle of a state that partially governs personal actions to promote unity. In Whitman's poetry, especially in Leaves of Grass, the balance between individual freedom and state ideals is often unclear, prompting questions about the relationship between personal liberty and collective duty. A notable clue that "When I Heard the Learn’d Astronomer" delves into personalism is the phrase "wander’d off by myself" in line 6, which emphasizes the speaker's solitary interaction with the night sky.

Whitman contrasts the speaker's lone experience with the stars against a group of scientific observers applauding the astronomer, initially highlighting the importance of a personal and distinct contemplation of astronomy. By leaving the lecture room, the speaker can immerse himself in a mystical appreciation of the stars, avoiding feelings of being "tired and sick" or dissatisfied. This suggests that the speaker's personal freedom allows him to occasionally experience the profound and majestic significance of the stars.

Nonetheless, akin to Whitman's exploration of romanticism, there are subtle hints that this individualistic approach has its complexities. The speaker is described as "unaccountable," or inexplicably unable to remain in the lecture room, indicating this intricacy. His "wander[ing]" away from the scientific truths and mathematical figures in the first quatrain, along with his silent, solitary observation that yields no conclusions about the stars, implies that individualism alone does not resolve the poem’s dilemmas. While mathematics might not evoke the vivid imagery of the second quatrain, this imagery could distract from the deeper understanding of astronomy achievable through collective efforts. This ambiguity in Whitman's personalism theory within the poem underscores the delicate balance between individual desire and group cohesion.

Whitman's poem delves into the theme of astronomy to explore a range of ideas and comments on...