Final answer:
Nick exhibits both admiration and pity toward Gatsby's intense investment in his unattainable dreams, with the evocative language in the text highlighting the grandness and futility of Gatsby's pursuits.
Step-by-step explanation:
Nick's attitude toward "the colossal vitality of his [Gatsby's] illusion" is somewhat ambivalent, acknowledging both the grandness and the futility of Gatsby's dreams. The language Nick uses reveals a mixture of admiration and pity. Fitzgerald employs evocative language to depict the strength of Gatsby's belief in his dream, highlighting the intensity and persistence of Gatsby's aspirations despite their unreachable nature. An example from the text is where Nick reflects on Gatsby's hope against overwhelming odds: "Gatsby believed in the green light, the orgastic future that year by year recedes before us. It eluded us then, but that's no matter—tomorrow we will run faster, stretch out our arms farther… And one fine morning—". This imagery of the green light, representing Gatsby's undying hope and unattainable dreams, illustrates Nick's view of Gatsby's deep conviction and ultimately fruitless pursuit.