Theseus has but a brief role in A Midsummer Night's Dream. Theseus is first of all the representative of order and reasonableness and rational thought. He is the Duke of the province and responsible for settling legal disputes. Such disputes can even be of the sort between family members such as Egeus brings before him in I.i, that of how to get Hermia to marry Demetrius when she is in love with Lysander. At the end of the play, and Theseus appears only in the beginning and ending, Theseus, though he sympathizes with the young couples discovered asleep in the forest and rules in their favor, discredits their talk of fairies and enchantments as fantasies:
More strange than true: I never may believe
These antique fables, nor these fairy toys.
Fairies oppose rational thought, thus Theseus's rejection of the couples' story underscores his representation of rational thought, a representation first developed in Act 1. That he is also reasonable and not dogmatic is shown when he chooses in IV.i to rule in favor of Hermia and Lysander, Helena and Demetrius, instead of Egeus:
Fair lovers, you are fortunately met:/ ... /
Egeus, I will overbear your will;
For in the temple by and by with us
These couples shall eternally be knit:
Theseus's most famous speech, "The lunatic, the lover and the poet / Are of imagination all compact [are made completely of imagination]" (V.i), further underscores his representation of order, reason, and rational thought. He ends his speech by describing the extremes wrought by imagination: On the one hand, if imagination can think of a joy to be had, it immediately identifies someone through whom that joy can be delivered. On the other hand, in a fearsome dark night, if imagination fears, it immediately finds cause for fear in a bush that is "supposed a bear":
That if it would but apprehend some joy,
It comprehends some bringer of that joy;
Or in the night, imagining some fear,
How easy is a bush supposed a bear!