Shasta states that she was on a 'Three Hour Tour' when Doc was looking for her. These words are straight out of the theme song to the TV show Gilligan's Island.
Reese Witherspoon was attached to play Amy Adams' role in director Paul Thomas Anderson's previous film, The Master, but dropped out. She appears in this film.
Inherent Vice (2014) marks the first time that Paul Thomas Anderson has made a feature film distributed by a major Hollywood film studio - Warner Bros. Pictures - since when Columbia Pictures distributed his film, Punch-Drunk Love (2002).
In the restaurant discussing the Golden Fang, Doc and Sauncho Smilax bring up Howard Hughes and his purchases in Las Vegas real estate. The movie takes place in 1970, Howard Hughes dies in 1976, yet Doc refers to Howard Hughes in the past tense when he says, "Howard Hughes was Italian?" as if he were dead.
At the dentist's office the receptionists asks for "contact information"- a term not coined until the 21st century. In 1970, one would ask only for "a phone number" or "address."
In the same café scene with Doc and Bigfoot, Doc takes a drag off of a cigarette and clearly stubs it out in the ashtray with his right hand. Bigfoot then tells him to pick a card, which he does. Doc looks at the "card", taking a deep drag off another cigarette with his left hand. There was no time in between cuts for Doc to have lit another cigarette.
Sortilège: [Opening Lines]
She came along the alley and up the back steps the way she always used to. Doc hadn't seen her for over a year. Nobody had. Back then it was always sandals, bottom half of a flower-print bikini, faded Country Joe & the Fish t-shirt. Tonight she was all in flatland gear, hair a lot shorter than he remembered, looking just like she swore she'd never look.