Quince is assigning the roles because he is the one who wrote the play, calling it "The Most Lamentable Comedy and Most Cruel Death of Pyramus and Thisbe." Because he is the playwright, he is allowed to assign the various parts. This suggests that Shakespeare had the same privilege.

While the subject of the play seems in questionable taste to celebrate a marriage, ending as it does with the tragic suicide of two young lovers, the other mechanicals, such as Bottom, respect Quince's abilities. Quince does appear to have thought carefully about who should be cast in what role and to have fashioned the play with certain people in mind.

The play is certainly based on Ovid's story of Pyramus and Thisbe in the Metamorphoses, showing that Quince is literate and reasonably well read in the classics. It would also be common to adapt a play in this way from another source.

All of these actors/workers have a specific job for which their name is derived. Peter Quince is a carpenter. Although all of these workers are common tradesmen, a carpenter would be socially viewed as slightly above other workers, thus making him "more important" than the other workers who are more like finishers for a product, i.e. a mender, a joiner, a weaver, etc. Shakespeare was sticking to societal roles when assigning the carpenter as the writer and director of the play.

Quince is the director of the play, and he has determined which person would be best for each part. His choice of Snug to play the lion shows that he is taking into account the strengths of the men - Snug has trouble remembering lines.

At the end of the scene Quince asks them to meet a mile outside of town at the duke's oak that night so they can practice without onlookers. They leave, with Quince saying that he will make a list of the props that they will need to present their play.