Explain the Main Weaknesses of Bentham’s Version of Utilitarianism

Jeremy Bentham never classed himself as, or was classed by others in his time as an Act Utilitarian. This is merely a label that has been assigned to him in future years, to solidify and categorise his ethics in somewhere by which an onlooker can begin to understand them. However, Act Utilitarianism ethics throw up many weaknesses, many of which can be deeply scrutinized and developed.
One of the main weaknesses of Bentham’s version of Utilitarianism is that there is the potential to justify any act. This is because Bentham’s version is based, yes on the consequences of an action, but on the pleasure gained from an action. For example, if seven men were walking down an alley and stabbed a girl to death, then according to Bentham’s device ‘The Hedonic Calculus’ the amount of the men’s pleasure would completely outweigh the amount of the woman’s pain, and would therefore make the action of killing the women morally right. This is a huge flaw in his reasoning, as to 99% of people murder is ultimately always wrong.
Another weakness one could pick out of Bentham’s version of Utilitarianism is that there is huge difficulty in weighing up how much pleasure is actually achieved from an action. In the same example as the last, take 3 men and replace them with women, so we have 4 a side. The men continue to beat the women. Does the women’s pain now outweigh the men’s pleasure? Or is it still the latter? Some may say that by using Bentham’s hedonic calculus we can measure pleasure, but in reality it is nigh on impossible to weigh up side by side with pain.
Continuing along with the last criticism, Bentham relies a lot on measurement of pleasure and pain to come to a morally right decision in his version of Utilitarianism. Not only is this a huge flaw as I have previously stated, but to measure up consequences is another big weakness. Surely consequence is not measurable because we do not know when a consequence will end? For example, a man falls over in the street, but a...