Cat On A Hot Tin Roof: Theme Analysis

Lies vs. Truth
When in Act 2 Brick blurts out to his father that he is disgusted with all the "mendacity" in life, he gives expression to the play's major theme: the tension between the lies that people tell themselves and others, and the truth, which may be hard to stomach but must come out in the end.
The Pollitt household is not a place where the truth is easily expressed. Brick is hiding something in his emotional life that he cannot bear to look at closely-until he is forced to by Big Daddy. He is disgusted with the fact that society would misinterpret the purity of his friendship with Skipper and turn it into something else. Gooper and Mae pretend to be the dutiful, attentive son and daughter-in-law, when in truth they are driven solely by the desire for material gain. Big Mama hides behind the illusion that her husband does not really mean all the cruel things he says to her. Big Daddy tells Brick he is disgusted with all the lies he has had to tell over the years, such as pretending that he cares for his wife and for Gooper, Mae and his grandchildren, when the truth is that he cannot stand any of them. Even Maggie, who of all the characters tends to see things clearly, is willing to lie to get what she wants. This is seen when she tells the family in the final moments of the play that she is pregnant.
Sometimes the distinction between truth and falsehood is obscured by the fact that each character sees the others through the distorting lens of his or her ego. Big Daddy, for example, thinks that his wife is merely scheming to take over the plantation; because he does not love her, he projects that lack of love onto her. At the end of the play, Brick reveals a similar attitude. He sounds surprised at Maggie's declaration of love for him, but he may simply be assuming that because he is indifferent towards her, she must also be that way towards him.
The major deception in the play is practiced by the entire family, in cooperation with Dr. Baugh, on Big Daddy. They tell him (and initially Big Mama as well) that he is suffering from a "spastic colon," when in reality he is dying of cancer.
Given the lies that are at the heart of these characters' lives, the scene between Big Daddy and Brick in Act 2 is especially important. They will not let each other rest in illusions or refuse to face the truth. Big Daddy's words to Brick, "Then there is at least two people that never lied to each other" (p. 113) is an expression of the bond between them.
Homosexuality
Homosexuality is the "inadmissible thing" (Williams' note, p. 116) that hovers in the background of the play. The room in which the action takes place is the same room that was occupied for so many years by the former owners of the plantation, Jack Straw and Peter Ochello, who were homosexual lovers.
Big Daddy has a tolerance for homosexuality. He speaks affectionately of Ochello, who gave him his opportunities in life. But his tolerance is not shared by Brick, who is horrified when he gets the idea that his father thinks he may be homosexual. Brick is heavily influenced by how society regards homosexuality. As a handsome pro-football player and TV sports announcer, Brick has lived for years on the approval and high regard of society. He cannot bear the scorn that would result from being branded a homosexual. He refers to homosexuals as "fairies," "dirty old men" and "queers," insisting that his friendship with Skipper was "deep, deep friendship . . . clean and decent" (p. 122), nothing to do with sex at all. Skipper's fear of what others might think is in contrast to Big Daddy, who says he has "lived with too much space around me to be infected by ideas of other people" (p. 122).
The truth about Brick's sexuality is hard to determine. No one in the play regards him as a homosexual, but it is possible that he represses his own desires. On the face of it, Skipper appears to have been the homosexual one, but again, even that is not an established fact. Maggie thought that because Skipper and Brick had an exceptionally close friendship, Skipper must be a homosexual. It was she who (at least according to her view of events) convinced Skipper of it. Tennessee Williams deliberately leaves the issue fraught with ambiguity.