Scholars have found it extremely difficult to assign one specific, overarching theme to the play. Proposals for a main theme include a discovery by the characters that human beings are neither wholly good nor wholly evil, but instead are more or less alike, awaking out of a dream and into reality, the danger of hasty action, or the power of tragic fate. None of these have widespread support. However, even if an overall theme cannot be found it is clear that the play is full of several small, thematic elements that intertwine in complex ways. Several of those most often debated by scholars are discussed below.
"Romeo If I profane with my unworthiest hand This holy shrine, the gentle sin is this: My lips, two blushing pilgrims, ready stand To smooth that rough touch with a tender kiss. Juliet Good pilgrim, you do wrong your hand too much, Which mannerly devotion shows in this; For saints have hands that pilgrims' hands do touch, And palm to palm is holy palmers' kiss."—Romeo and Juliet, Act I, Scene V
Romeo and Juliet is sometimes considered to have no unifying theme, save that of young love. Romeo and Juliet have become emblematic of young lovers and doomed love. Since it is such an obvious subject of the play, several scholars have explored the language and historical context behind the romance of the play.
On their first meeting, Romeo and Juliet use a form of communication recommended by many etiquette authors in Shakespeare's day: metaphor. By using metaphors of saints and sins, Romeo was able to test Juliet's feelings for him in a non-threatening way. This method was recommended by Baldassare Castiglione (whose works had been translated into English by this time). He pointed out that if a man used a metaphor as an invitation, the woman could pretend she did not understand him, and he could retreat without losing honour. Juliet, however, participates in the metaphor and expands on it. The religious metaphors of "shrine", "pilgrim" and "saint" were fashionable in the poetry of the time and more likely to be understood as romantic rather than blasphemous, as the concept of sainthood was associated with the Catholicism of an earlier age. Later in the play, Shakespeare removes the more daring allusions to Christ's resurrection in the tomb he found in his source work: Brooke's Romeus and Juliet.
In the later balcony scene, Shakespeare has Romeo overhear Juliet's soliloquy, but in Brooke's version of the story her declaration is done alone. By bringing Romeo into the scene to eavesdrop, Shakespeare breaks from the normal sequence of courtship. Usually a woman was required to be modest and shy to make sure that her suitor was sincere, but breaking this rule serves to speed along the plot. The lovers are able to skip courting, and move on to plain talk about their relationship— agreeing to be married after knowing each other for only one night. In the final suicide scene, there is a contradiction in the message—in the Catholic religion, suicides were often thought to be condemned to hell, whereas people who die to be with their loves under the "Religion of Love" are joined with their loves in paradise. Romeo and Juliet's love seems to be expressing the "Religion of Love" view rather than the Catholic view. Another point is that although their love is passionate, it is only consummated in marriage, which keeps them from losing the audience's sympathy.
The play arguably equates love and sex with death. Throughout the story, both Romeo and Juliet, along with the other characters, fantasise about it as a dark being, often equating it with a lover. Capulet, for example, when he first discovers Juliet's (faked) death, describes it as having deflowered his daughter. Juliet later erotically compares Romeo and death. Right before her suicide she grabs Romeo's dagger, saying "O happy dagger! This is thy sheath. There rust, and let me die."
Fate and chance
"O, I am fortune's fool!"—Romeo, Act III Scene I
Scholars are divided on the role of fate in the play. No consensus exists on whether the characters are truly fated to die together or whether the events take place by a series of unlucky chances. Arguments in favour of fate often refer to the description of the lovers as "star-cross'd". This phrase seems to hint that the stars have predetermined the lovers' future. John W. Draper points out the parallels between the Elizabethan belief in the four humours and the main characters of the play (for example, Tybalt as a choleric). Interpreting the text in the light of humours reduces the amount of plot attributed to chance by modern audiences. Still, other scholars see the play as a series of unlucky chances—many to such a degree that they do not see it as a tragedy at all, but an emotional melodrama. Ruth Nevo believes the high degree to which chance is stressed in the narrative makes Romeo and Juliet a "lesser tragedy" of happenstance, not of character. For example, Romeo's challenging Tybalt is not impulsive; it is, after Mercutio's death, the expected action to take. In this scene, Nevo reads Romeo as being aware of the dangers of flouting social norms, identity and commitments. He makes the choice to kill, not because of a tragic flaw, but because of circumstance.
Duality (light and dark)
"O brawling love, O loving hate, O any thing of nothing first create! O heavy lightness, serious vanity, Misshapen chaos of well-seeming forms, Feather of lead, bright smoke, cold fire, sick health, Still-waking sleep, that is not what it is!"—Romeo, Act I Scene I
Scholars have long noted Shakespeare's widespread use of light and dark imagery throughout the play. Caroline Spurgeon considers the theme of light as "symbolic of the natural beauty of young love" and later critics have expanded on this interpretation. For example, both Romeo and Juliet see the other as light in a surrounding darkness. Romeo describes Juliet as being like the sun, brighter than a torch, a jewel sparkling in the night, and a bright angel among dark clouds. Even when she lies apparently dead in the tomb, he says her "beauty makes This vault a feasting presence full of light." Juliet describes Romeo as "day in night" and "Whiter than snow upon a raven's back." This contrast of light and dark can be expanded as symbols—contrasting love and hate, youth and age in a metaphoric way. Sometimes these intertwining metaphors create dramatic irony. For example, Romeo and Juliet's love is a light in the midst of the darkness of the hate around them, but all of their activity together is done in night and darkness, while all of the feuding is done in broad daylight. This paradox of imagery adds atmosphere to the moral dilemma facing the two lovers: loyalty to family or loyalty to love. At the end of the story, when the morning is gloomy and the sun hiding its face for sorrow, light and dark have returned to their proper places, the outward darkness reflecting the true, inner darkness of the family feud out of sorrow for the lovers. All characters now recognise their folly in light of recent events, and things return to the natural order, thanks to the love and death of Romeo and Juliet. The "light" theme in the play is also heavily connected to the theme of time, since light was a convenient way for Shakespeare to express the passage of time through descriptions of the sun, moon, and stars.
"These times of woe afford no time to woo."—Paris, Act III Scene IV
Time plays an important role in the language and plot of the play. Both Romeo and Juliet struggle to maintain an imaginary world void of time in the face of the harsh realities that surround them. For instance, when Romeo swears his love to Juliet by the moon, she protests "O swear not by the moon, th'inconstant moon, / That monthly changes in her circled orb, / Lest that thy love prove likewise variable." From the very beginning, the lovers are designated as "star-cross'd" referring to an astrologic belief associated with time. Stars were thought to control the fates of humanity, and as time passed, stars would move along their course in the sky, also charting the course of human lives below. Romeo speaks of a foreboding he feels in the stars' movements early in the play, and when he learns of Juliet's death, he defies the stars' course for him.
Another central theme is haste: Shakespeare's Romeo and Juliet spans a period of four to six days, in contrast to Brooke's poem's spanning nine months. Scholars such as G. Thomas Tanselle believe that time was "especially important to Shakespeare" in this play, as he used references to "short-time" for the young lovers as opposed to references to "long-time" for the "older generation" to highlight "a headlong rush towards doom". Romeo and Juliet fight time to make their love last forever. In the end, the only way they seem to defeat time is through a death that makes them immortal through art.
Time is also connected to the theme of light and dark. In Shakespeare's day, plays were most often performed at noon or in the afternoon in broad daylight. This forced the playwright to use words to create the illusion of day and night in his plays. Shakespeare uses references to the night and day, the stars, the moon, and the sun to create this illusion. He also has characters frequently refer to days of the week and specific hours to help the audience understand that time has passed in the story. All in all, no fewer than 103 references to time are found in the play, adding to the illusion of its passage.