In Orwell's classic novel 1984, War is Peace, Freedom is Slavery, and Ignorance is Strength are the Party's three paradoxical slogans, which are perfect examples of how the ruling government uses language to manipulate and control the population's thought processes. Winston gains insight into the meaning of the Party's three slogans when he reads Emmanuel Goldstein's book titled THE THEORY AND PRACTICE OF OLIGARCHICAL COLLECTIVISM.

"War is Peace" refers to the way in which the Party uses continual warfare to control and oppress the population. Oceania is constantly at war with either Eurasia or Eastasia, which cultivates an atmosphere of hysteria, continually bolsters patriotism, and wastes valuable resources and energy that would otherwise be used to increase the standard of living. The result of constant warfare is a fearful, obedient population that is willing to make substantial sacrifices for their country. Therefore, war creates peace and stability throughout Oceania.

The slogan "Freedom is Slavery" means that individualism and autonomy result in slavery and persecution. In Oceania, individuality is prohibited, and citizens are required to be part of a collective group. According to O'Brien,

The individual only has power in so far as he ceases to be an individual...Alone—free—the human being is always defeated (333).

Once a citizen embraces the concept of collectivism and views themselves as an integral part of a group, they are considered free by Party standards. The third slogan, "Ignorance is Strength," refers to the way the Party benefits from an ignorant, simple population. In Oceania, the government's primary goal is to maintain its complete authority. In order to remain omnipotent, the Party suppresses knowledge, censors literature, alters language, and spreads propaganda. These efforts create an ignorant population, and the citizens are unable to recognize their oppressed status or rebel against the government. Therefore, the population's ignorance makes the Party strong, which corresponds to the slogan.

This novel is constructed through paradox and contrasts. These three slogans of the Party reflect these aspects, in that the way the Party controls Oceania is actually the opposite of the propaganda it produces. Thus, according to the Party, "war is peace" means that they continually "fight" wars in order to keep peace at home. During times of war, nations generally unite. Of course, if the people are focused on a common enemy, they are much less inclined to notice how unhappy they are in their own lives. So they make less trouble for their government. "Freedom is slavery" can be thought of in the same way: the slavery of Party members equals freedom for Party leaders. Finally, "Ignorance is strength" can be read "Your ignorance is our strength", again meaning that the ignorance of the people translates into the strength of the government.

It goes directly into the concept of doublethink, which Emmanuel Goldstein explains through the word "blackwhite":

But it means also the ability to believe that black is white, and more, to know that black is white, and to forget that one has ever believed the contrary. This demands a continuous alteration of the past, made possible by the system of thought which really embraces all the rest, and which is known in Newspeak as doublethink. Doublethink is basically the power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them.

"Doublethink" is the epitome of paradox, and is the key to the Party's control. Through this concept, people can essentially "forget" the past, even when the Party changes that past weekly. Coupled with their propaganda, it makes it nearly impossible for anyone to verify their thought...or even want to. If you can't look up the story you thought you heard last week, how can you be sure what the truth truly is?

At first glance, these slogans seem to be contradictory and illogical.  And, they pretty much are, but the society in 1984 is run by a group of people that have pretty much brainwashed or intimidated the entire population into believing whatever sort of nonsense they promote.  So, these three slogans are lived by and sworn by, and the essence of everything that the Party represents. Each of these three slogans have double meanings--one for the Party and one for the people as a whole.

First of all, let's look as War is Peace.  In their society, keeping the masses believing that constant war is being waged is actually a way of maintaining peace.  War elicits great patriotism and devotion to country; it also promotes sacrifice and giving to the community over oneself. So, if there is constant war, the people are constantly giving, sacrificing, and pledging devotion to their government.  This keeps the people in check and in control, and hence, peaceful.  That is how the Party uses that slogan.  The people think it just means that world peace is maintained through war.  Without war, their security would be threatened.

Freedom is slavery is more tricky. The people probably believe that to mean that having total freedom is actually a way to become enslaved to your senses, weaknesses and vices.  For example, the Party encourages young women to remain virtuous and restrict themselves from being romantically involved or sentimental in any way.  The society has firm beliefs about sex and relationships--there is very little freedom there, because they feel that sex and relationships enslave people.  If you are constantly embroiled in relationships, you are subject to the turmoil and unhappiness that they sometimes cause, and are constantly thinking about it.  That is not freedom, according to them.  So, to the people and the masses, they have been taught that freedom to act, and sometimes act poorly, actually tends to enslave one to sentimental and unessential vices and emotions.  To the Party, a free people represents the removal of their power.  So, the people must not be free in order to remain in power.

To the masses, being ignorant about the true condition of things is actually beneficial, because it helps them to remain happy and optimistic, and thus strong.  To the workers within the Party, like Winston, their entire jobs rely on keeping the people ignorant of true facts and statistics.  Essentially, lie to keep the people in the dark, and then the Party--and their jobs--will always be strong.  The people's ignorance gives the Party strength; if they really knew the true state of things and how they had been manipulated, they would rebel, and take away the Party's power.

In the end, it all comes down to the Party creating slogans that ensure the continuation of their power and control.  I hope that helps; good luck!

The answer rests with the paradoxical nature of the Party itself. How it rules is the exact opposite of how its propaganda says it controls.It goes directly into the concept of doublethink, which Emmanuel Goldstein explains through the word "blackwhite":

But it means also the ability to believe that black is white, and more, to know that black is white, and to forget that one has ever believed the contrary. This demands a continuous alteration of the past, made possible by the system of thought which really embraces all the rest, and which is known in Newspeak as doublethink. Doublethink is basically the power of holding two contradictory beliefs in one's mind simultaneously, and accepting both of them.

Thus, according to the Party, "war is peace" means that they continually "fight" wars in order to keep peace at home. During times of war, nations generally unite. Of course, if the people are focused on a common enemy, they are much less inclined to notice how unhappy they are in their own lives. So they make less trouble for their government. "Freedom is slavery" can be thought of in the same way. the slavery of Party members equals freedom for Party leaders. Finally, "Ignorance is strength" can be read "Your ignorance is our strength", again meaning that the ignorance of the people translates into the strength of the government.

These are the paradoxes under which Oceania operates.  "War is Peace" seems like it couldn't possibly be true, but Oceania is at war with its own people...the government suppresses them into submission and obedience.  As long as they follow the rules, there is peace, even though there is the constant premise of war with one of the other countries.

"Freedom is slavery" seems untrue as well, however, upon closer inspection, that is exactly what is happening in Oceania.  The Proles, who are the most free, are also the most impoverished...enslaved by their lack of money but free to do all other things including wearing makeup, singing, etc.  The Party members have more "freedom," but they are enslaved by overbearing rules and also the fear of the consequences should they break the rules.  Room 101 is the most enslaving factor.

"Ignorance is strength" is also true, although it seems a serious contradiction.  Winston constantly mentions that the strength is with the Proles.  They are the largest population in Oceania, and they are the most ignorant.  There are no telescreens or rules in the Proles' community.  They are the dumb masses...not realizing that they are the sole people who are capable of rebelling and winning true freedom for everyone.  However, they are blissfully happy in their ignorance, so there is no reason for them to rise up. They are poor, but they have just enough to survive and find some semblance of happiness. 

Each of these sayings seems contradictory and that feeds into the themes of the novel: freedom and enslavement, loyalty and betrayal, appearances and reality.  All of those are somewhat contradictory, too.  Orwell's book is meant to show what happens when absolute power corrupts absolutely which is what has happened in the world of the story.  The government has so much power over the people they can create their own reality which they have done.  The government of the fictional Oceania has a different interpretation of the slogans however.  For them, "War is peace" means that as long as they can keep the war machine moving, there is peace.  As long as they can keep people fighting the war and making implements with which to fight the war, then the people have no time to fight the government.  Therefore, for the government, there is peace.  "Freedom is slavery" is a bit more complex.  The Party (the government) is doing all it can to enslave the people, but it doesn't want them to think they are enslaved.  So, they brainwash the people.  They try to convince the populace that what some perceive as "freedom" is really nothing more than being tied to a doctrine which enslaves them.  Of course, the irony is obvious.  They are the ones with the doctrine that ties people to it. "Ignorance is strength" means that if the Party can keep the people ignorant of the truth then the Party is strong.  One of the main and one of the worst qualities of the Party is that it constantly rewrites history to suit its purpose.  That is, in fact, Winston Smith's job.  They keep people ignorant of the facts, they pump propaganda at them 24/7 and that keeps the Party strong. The Party wants people to see the slogan, however, as a way of consoling them to the idea that they, the people, don't need to be aware of all information.  They want people to see the Party as one who looks out for them and in doing so, takes on the burden of knowing what is good for them so the people don't have to be burdened with this information.  There is much more to each of these three slogans, I've only brushed the surface.  They are key to the novel and bear looking into further on your part.