It is in this chapter, through the articulate and intelligent Syme, that we first begin to understand the extent of the Party's ambitions (these ambitions are, of course, completely explained by O'Brien in his interrogation of Winston later in the book). A key theme of 1984 is the power of language. This is demonstrated through the use of the pithy and apparently oxymoronic Party slogan "War is Peace; Freedom is Slavery; Ignorance is Strength." In his lunchtime conversation with Winston, Syme, who is responsible for editing the dictionary of Newspeak, outlines exactly how language can be used to subjugate people. Syme's job is, as he puts it, "the destruction of words." He and his colleagues are paring down the English language, simplifying it by getting rid of what they deem unnecessary adjectives, antonyms of certain words, and other superfluities. But the Party's aims go beyond simplifying the language, and they are not doing it for the sake of efficiency. For them, it is another exercise in mind control. Syme explains:

Don't you see that the whole aim of Newspeak is to narrow the range of thought? In the end we shall make thoughtcrime literally impossible, because there will be no words in which to express it. Every concept that can ever be needed, will be expressed by exactly one word, with its meaning rigidly defined and all its subsidiary meanings rubbed out and forgotten. 

If the Party controls language, then they control the range of ideas that can be expressed. And in this way they can eliminate the ability to articulate opposition to the Party. Syme tells Winston that "orthodoxy means thoughtlessness." The Party not only demands unthinking, unquestioning loyalty, it seeks to eliminate the possibility of any other emotion. 

But Syme's conversation with Winston reveals another element to the Party's philosophy. Winston recognizes that Syme is far too intelligent for his own good. He will be, Winston thinks to himself, eventually "vaporized." The stupid, obsequious Parsons, who eventually joins their conversation, on the other hand, will never be vaporized, he thinks. 

So it is in this chapter that we really learn the extent of the Party's control of the people. Syme demonstrates how the Party uses language itself to control what people can think.

In the conversation between Winston and Syme we learn about the Party's plan to reduce the language to as few words as possible. This new language is called Newspeak. Syme, who is working on the Newspeak dictionary, is quite enthusiastic about this project. He also understands that the goal is to take away the possibility of people having unorthodox or forbidden thoughts by taking away the words they could use to think them.

From this, we learn that the Party is looking to control people and encourage simple-minded obedience, not develop sophisticated thinkers. It is more concerned with control than freedom. We also learn, as Winston ruminates on Syme's dangerous level of perception, that the Party is quite willing to wipe out people, like Syme, who are too intelligent: Winston is convinced that Syme will soon disappear. 

In their canteen at work, Winston has a conversation with Syme, who is an expert in the Party's Newspeak language. During their conversation, Winston asks him about the new edition of the Newspeak dictionary he is working on. Syme displays enthusiasm:

We’re destroying words—scores of them, hundreds of them, every day. We’re cutting the language down to the bone. 

Syme will then accuse Winston of not appreciating the beauty of destroying redundant words and of clinging to the vagueness of Oldspeak. 

Syme cuts to the heart of the Party's philosophy in promoting Newspeak: it is to eradicate thinking. 

Don’t you see that the whole aim of Newspeak is to narrow the range of thought? In the end we shall make thoughtcrime literally impossible, because there will be no words in which to express it. Every concept that can ever be needed, will be expressed by exactly one word, with its meaning rigidly defined and all its subsidiary meanings rubbed out and forgotten. Already, in the Eleventh Edition, we’re not far from that point. But the process will still be continuing long after you and I are dead. Every year fewer and fewer words, and the range of consciousness always a little smaller.

In other words, Syme reveals the party's desire to control people by limiting language and hence limiting the very ability to construct independent thoughts. 

"Orthodoxy is unconsciousness," is how Syme sums it up.

At this point, Winston realizes that Syme will be vaporized because he is too intelligent.

When Winston reads The Book about the secret aims of the party, this will confirm Syme's words: the goal of the party is to stay perpetually in power, and it believes it can achieve this in part by controlling language and hence people's ability to formulate any opposition to its aims. The philosophy of the party is to hold power at any cost, even if it means sacrificing the sophisticated thought patterns that make people human.

A fascinating question.
Those conversations reveal that ambitious sweep of the philosophy. By reworking language, they hope and plan to make it impossible for people to think independently, or, indeed, to think in any way that does not support their goals. Syme's other comments indicate how much the Party is driven by hatred, and how much class antagonism there is in the Party (look at how he says the proles aren't really people).