In Fahrenheit 451, Ray Bradbury attempts to convey a number of messages but I feel one of the most prominent and important themes is as such: Humans need to have intellectual freedom and depth in order to truly live and be happy. In "The Hearth and the Salamander" and shortly into "The Sieve and the Sand", we're introduced to three types of people.
	Mildred Montag is the first and most prominent example of people in this novel; she's shallow, unhappy, distant from other humans like Guy. She's the stereotypical blinded and pacified American that America itself created and is the product of a lack of intellectual stimulation. Guy at one point in the story asks her "When was the last time you were really bothered about something? Something important?" and this one question, and her refusal to answer, tells us how much Mildred really cares about the world. Tells us how much she cares about her problems, thinking, storylines and everything else that's deeper than a depression in dirt made by a shoe.
	Then we have people like Guy Montag, who are also unhappy and largely uneducated but have the potential to change that and/or are looking for intelligence. Throughout the story, ever since his gradual change in personality after meeting McClellan, he is seen as not being happy with his life but instead of simply resigning to immediate gratification as the rest of society does, he asks questions, he thinks and attempts to experience nature. This difference between him and the norm is apparent in two places that stick out prominently in my mind. In "The Hearth and the Salamander", Guy runs into Clarisse while it's raining and sees that she's letting the rain fall into her mouth. After they have a brief conversation, which in itself is unusual, he follows suit and tastes the rain like she did (Page 24, Bradbury). While it may not be directly implied, I understood from this that Guy did this because he's a unique individual and that he came away from the situation with a little bit of happiness, a little bit of insight or even both. The second event that sticks out in my mind is at the very end of the book, which shows a stark contrast from how he was in the beginning of the story and his growth to the third type of character I am soon to discuss. Once Guy Montag reaches the river and starts experiencing nature, almost immediately he becomes awestruck by the world he's been missing. He feels calmer, more free and that he can finally start understanding the world in a new light. "He felt as if he had left a stage behind and many actors. He felt as if he had left the great seance and all the murmuring ghosts..." (pg. 140, Bradbury). This sort of mentality is oft felt by people of the third type at some point in their lives.
	This third group of people is populated by those who have seen what glory, mystery, power and greatness books can hold. People such as Faber, Beatty, Clarisse and Guy at the end of the story are such people. This group is unique, though, in the fact that Beatty has a twist that's very unlike everyone else in the group. It is implied that when he was younger, he read countless books and was very much in love with them but his personal life made him resent books. On the later half of page 169 and 170, Bradbury reveals a part of what he might have included in the book that pertains to Beatty. It turns out that Beatty was to have tons of books on his property but would never read them. Bradbury later goes to imply that books no longer had the same effect on him as they used to due to life getting to him, and thus he ends up resenting them. All the same, though, this third group of people are people that are most similar to those that live in our current society in the way that they have managed to have independent, deep and critical thought. For some, like Beatty, they've yet to achieve happiness while others, like Clarisse, they've practically achieved the closest thing one could have to nirvana in such a society.
	These three groups of people are used as examples of causes and effects, with each group showing different causes that get progressively more advanced intellectually and thus, each effect is more desirable than the last. No matter how one words it, one will never be able to properly define the cause and effects of each group but a basic interpretation of the causes and effects can be seen as such: 1) If one does not expand one's intellectual capacity, then one will never be happy. 2) If one attempts to expand one's intellectual capacity, then one will either a) give up and revert to cause-effect 1 or b) persevere until finding closure. 3) If one successfully attempts to expand one's intellectual capacity, and thus achieve higher thinking, then one will have a possibility to be happy. In this way, by telling the reader indirectly that the shallow ones are not happy and the intellectuals can be, Bradbury tells us that having freedom of thought and the ability to think in the first place is a positive trait and is a necessity for humanity to thrive and move forward.