Although my initial incentive was to bop him on the head, I restrained myself and calmly told him that he is an idiot. Where does Walt necessarily disagree with science? He doesn't. It is an assumption on my idiot brother's part that he is drawing a thick line between mechanical theory and natural beauty. The narrator only expresses his disgust for the "professor" subject, as well as the lecture-room crowd, who is, perhaps, pretentious in his own right. He only dislikes the method with which Astronomy is presented. The poem's stark contrast between the two attitudes just serves to present Walt's opinion, which is that the subject CAN be more organic, and less robotic. By having the narrator veer towards one extreme over another, Walt ingeniously shows the possibility of middle ground.
I know that I just stated the Whitman and the narrative are the same; but the fact that the author and the narrator don't always have the same point of view doesn't necessarily imply that in this case, they have different points of view. Whitman was a follower of the Romantic tradition; by and large, his poems do reflect what he feels and believes. If he had wanted to, I'm sure he could have distanced himself from his narrator's point of view more explicitly; since he didn't, I assume that it wasn't his intention to do so.
Returning to the poem, note the wonderful quality of the verse itself. There is a common misconception that 'free' verse implies a total disregard