The idea in utilitarianism is that the moral worth of an action is determined solely by its value in providing happiness or pleasure as summed among all conscious beings. It is a form of consequentialism, meaning that the moral worth of any action is determined by its outcome. Thus the utilitarian maxim: the greatest good for the greatest number. The largest contributors to utilitarianism were Jeremy Bentham and John Stuart Mill. 
The objection that I am going to focus on in this essay is a broad one but also I believe the most important and valid objection to the theory. The objection is that Utilitarianism ignores individuals and individual rights.
John Rawls rises what I believe to be a very good point in his objection to utilitarianism as he focuses on the issues of rights, fairness and justice He asks is utilitarianism compatible with the notion of undeniable rights meaning the rights we all poses as human beings and that cannot be taken away from us and he then asks if a person could defend both views consistently. 
Rawls answers this question with a no, that is to say he doesn’t believe that one could be a utilitarian and maintain his individual rights. The reason being the principal goal in a utilitarian society is the happiness of the greatest number and not that of the individual. Utilitarian’s see society on the model of a super person, who can control, deny or delay the gratification of certain parts or persons for the sake of greater satisfaction of the whole. As a result the individuals who get in the way of the grand plan simply don’t matter. This can be interpreted basically as the individual has his rights only as far as him having them doesn’t interfere with the greatest happiness of the greatest number. 
Rawls argues that there is something intuitively unfair about this and probably isn’t the only one as Ayn Rand puts it ” individual rights are not subject to a public vote, a majority has no right to vote away the rights of a minority, the political function of rights is precisely to protect minorities from oppression by majorities and the smallest minority on earth is the individual.” 
The separateness of persons argument says that utilitarianism extends to society as a whole the principle of rational prudence for one person. Basically as that of an impartial, sympathetic spectator who imaginatively identifies with every other member of the society thus conflating all their desires within one experience.  This allows the society to balance individual needs and desires, gains and losses as if they were one individual. The problem with this of course is that a society is not one individual person. This approach treats the different individuals in a society as if they were of no more importance for ordering of society then the different stages of an individual’s life are for its ordering. But a society is composed of different and distinctly individual persons, each with its own life to lead, goals, ambitions, points of view, desires and so on. People cannot be simply cashed out for experience since boundaries between individuals are of far greater importance and in fact define the very object of moral concern.
These objections were also raised by Thomas Nagel who claimed that utilitarianism ‘treats the desires, needs, satisfactions, and dissatisfactions of distinct persons as if they were of a super person or one mass person’  as well as David Gauthier who said utilitarianism supposes that mankind is a so called super-person, whose greatest satisfaction is the objective of moral action.  This poses a huge problem as individuals are the ones with wants and needs not the mass person and its individuals who seek satisfaction not a mass person. Individual’s satisfaction is not part of any greater satisfaction. Aggregation of utility becomes pointless as both suffering and happiness are inseparable from the individual that feels them, rendering the task of adding up all the pains and pleasures of multiple individuals pointless and impossible.
The conclusion then is that the utilitarian must be mistaken because the denial of the separateness of persons can only be based on believing society to be a single aggregate super being. Because it denies the separateness of persons it actually doesn’t give equal concern to all persons rather giving equal concern to all interests and thereby ignoring the way in which various interests are integrated into individual human lives.
People are individuals, with their own personal lives they directly experience only their own happiness and unhappiness and since I am only capable of experiencing my own personal psychological states, it’s no compensation for me when I am unhappy that someone else is happy meaning that utilitarianism wrongly applies the model of individual decision making to interpersonal context. Mill’s greatest happiness principle says we should maximise happiness but it doesn’t say anything about the distribution of that happiness in certain circumstances, the distribution that maximises happiness overall may make some people very unhappy and it is surely wrong to do terrible things to undeserving people for the benefit of others, because this is unjust as per Rawls, this is a morally repugnant conclusion. 
Rawls as well as Nozick claim that utilitarianism doesn’t respect the fact that individuals are separate beings. It focuses exclusively on maximizing the greater happiness and fails to take into consideration in the proper way how utility is distributed among different individuals. For example a big moral problem is that utilitarianism sanctions injustice such as the slavery of a few as long as it benefits the majority. The reason for this is that it is a primarily collectivistic morality and as such places all its attention on aggregate happiness and fails to show proper respect to the individuals. As Nozick points out ” to use a person for another’s benefit does not sufficiently respect and take account of the fact that he is a separate person, that his is the only life he has. He does not get some overbalancing good from his sacrifice”. 
The problem for utilitarianism with this is not just that it approves clear injustice because to that utilitarians can respond with many reasons pointing out how injustice will not provide the greater good in the long run and as such injustice really wouldn’t be approved. The real problem is that even if it does reach the right conclusion it does so for the wrong reasons. The reason that I shouldn’t kill you is not that you being alive provides a greater good for the majority but because I have an obligation to you as an individual not to do so, to put it another way you have a right to live.
Utilitarianism broken down to its bare bones is the greatest good for the greatest number or the greatest happiness principle. It sets a framework for deciding which actions are morally good and which are bad. The theory is rooted in hedonism, or the idea that each individual is concerned only with actions that bring him pleasure and as a result concerned with actions that bring the society as a whole pleasure.
However, how much happiness the action results in is not defined with respect to the individual, because if the action brings happiness to the individual but unhappiness to many other individuals, then the ratio of unhappiness is higher. Therefore, by definition, utilitarianism concerns itself only with the consequences of an action, and whether those consequences increase happiness to the majority.
In answering how utilitarianism decides which rights an individual has we look at it this way. In utilitarianism the individual has a right to something if and only if that individual has a valid claim on society for that something’s protection, so rights are only justified if they are essential to happiness. Interestingly this is not applied both ways meaning if a right is not essential to happiness then society is not required to protect the right and as a result there exists only conditional rights for human beings in a utilitarian society. 
The problem as far as individual rights are concerned is that the greatest happiness principle is a purely aggregate principle only concerning itself with the overall amount of happiness. This of course poses a problem as far as individual rights are concerned, for example it could condone genocide. This is how this could happen, say the society exterminates a portion of the population say one hundred people and this creates happiness among a larger portion of the population say one million people then utilitarianism says this action is ok because the consequence of the action would promote general happiness or greater happiness as oppose to the suffering. Now genocide is clearly not a good thing our common sense and humanity tell us it is never acceptable to do such a thing. This is an example where there exists an extreme skew of the distribution of rights in a utilitarian society using the greater happiness principle.
There are a number of other examples where utilitarianism in my opinion fails and or comes to the wrong conclusion one being the riot case  , if a sheriff who could stop the riot by lying and imprisoning an innocent person whom he knew was innocent, a utilitarian would endorse imprisoning the innocent person because it would prevent the needless suffering of others should the riot continues. An innocent person is punished and this is justified simply because his imprisonment prevents future unjust acts from taking place. This is clearly wrong and goes against every intrinsic right we as human beings have.
Just because something makes people happy doesn’t make it right. Specifically it is wrong to harm certain individuals in order to make other people happy. Another great example of individual rights being ignored by utilitarianism is the inhospitable hospital case where an individual checks into the hospital for routine checks, there are three terminally ill people also at that hospital needing urgent organ transplants but no organs to give them in that situation the greater good principle would suggest that it is on to kill the healthy patient and harvest his organs to save the other two as this will result in the greatest amount of happiness or good. Now I know that there are some valid points utilitarian’s can make against such a situation ever happening in real life and what would happen to the ability of that hospital to deliver adequate health care should word get out that a healthy person has been cut up for his organs but never the less this hypothetical situation does provide in my view a good example that utilitarianism can come to some extremely bad conclusions and that the individual rights objection to the purest form of utilitarianism to my mind is in fact a decisive objection. Now there are other forms of utilitarianism which we simply cannot dive into in this paper.
I believe individual rights are of vital importance, especially in today’s day and age and I just cannot see the society the way Mills seems to imagine it. People are individuals with their own goals and ambitions and surely while I am willing to work harder so I can have that big screen plasma or that car I am simply not willing to work harder so Joe Bloke could have them. The idea of balancing of benefits to one person against harms to another that utilitarianism’s person neutrality requires would only be acceptable if there was interpersonal compensation but as the objection of individual rights or separateness of persons or whatever you want to call it shows: different people are distinct beings living separate lives and there is in general no interpersonal compensation. I cannot believe in sacrificing one individual life for another or worse for someone’s happiness or violating their sacred individual rights as human beings. I simply cannot see society as one super being where it’s ok for someone to give up their one and only life or