Love
In “since feeling is first,” the speaker tries to define the ideal form of love, and identify the priorities in a romantic relationship. The speaker’s version of a perfect romance is one that is felt before it is thought, one that involves intuition, sexual pleasure, and optimism, and one that is based on genuine actions rather than words. It is not one that is obsessed with social, linguistic, or cognitive constructs, or one that tries to verbally define itself.
How well does the poem itself actually live up to this ideal? The speaker somewhat “walks the walk” by not mentioning the word “love” in any part of the poem. Yet it remains ironic that the poem itself is an attempt to lay out the definition of true love, when the speaker's whole argument—indeed, the definition he arrives at—is that true love is precisely that love that can't be defined, least of all by carefully ordered words. Perhaps this irony shows how elusive of a concept love is.
Language
The word “syntax” initiates a debate within the poem about the capabilities and limitations of language. The speaker argues that attempts to contain love in ordered language—syntax—inevitably fail. The speaker also implies in the final two lines that linguistic constructs (the “paragraph” and “parenthesis”) are insufficient for describing complex concepts such as life and death.
And yet, the poem itself is, of course, an attempt to use language to express love. What makes this piece (as well as other poems by the author) successful is Cummings’s use of syntactical, phonetic, and typographic devices. In a sense, "since feeling is first" attempts to break language, like love, out of syntax. The poem makes us wonder: can love be defined? Does language, in its attempts to convey our feelings, imprison or liberate us? Can love exist without being spoken—can we exist without language?
Life and Death
The poem argues that life and death are beyond human understanding. They are not like paragraphs or parentheses; they are not things that can be simply read, written, erased, or ignored. They are also concepts that cannot be simply thrown in at the beginning of a poem: Human beings need to age, and get to the end of the page, in order to understand the meaning of life and death.
What adds an argumentative edge to this poem’s musings about life and death is the speaker’s attitude toward the brevity of the former and inevitability of the latter. The classic debate between carpe diem (seize the day; live in the moment) and memento mori (remember you must die; remember the finality of life) takes place in this love poem, and the speaker champions the former in urging the lady to stop crying, kiss and embrace her lover, and enjoy the pleasures of love and life. Is the speaker simply being the proverbial young lover? Or is the speaker making a valid argument about the way we should pursue our lives?