The speaker asks a chain of questions that move step by step from the inside outward. Thoughts become words, words become actions, and actions become "real." At each stage the speaker wonders whether the change loops back: will speaking alter the way I speak, will acting alter the way I think? The questions are open and a little wondering, as if the speaker is testing an idea aloud rather than lecturing.
The ending shifts from questions to a bold statement. The "above" and the "below" are both true, and so are the lie and the truth, "clear as the sun." That last line is puzzling on purpose. It suggests the speaker sees opposites existing side by side, perhaps inner life and outer life, or what we imagine and what we do. The quotation marks around "real" hint that the speaker doubts what counts as real at all. The mood is reflective and quietly mysterious, ending with a calm, almost startling certainty.