The Repugnant Conclusion, a philosophical thought experiment introduced by Derek Parfit in 1984, raises a challenging ethical dilemma regarding population ethics and the trade-off between overall well-being and the quality of individual lives. In this scenario, we are faced with choosing between two worlds: one with a high population and relatively low levels of happiness, and another with a smaller population but much greater happiness per individual.

 To approach this dilemma, we must consider different ethical frameworks and their implications. One perspective is that of total utilitarianism, which focuses on maximizing overall well-being or happiness. According to this view, the world with a higher population and lower levels of happiness would be preferable, as it would result in a greater overall sum of happiness.

 However, many find the Repugnant Conclusion deeply unsettling, as it seems counterintuitive to prioritize a larger population's overall happiness at the expense of the quality of individual lives. This has led to alternative ethical theories that emphasize the importance of individual well-being, such as average utilitarianism or prioritarianism.

 Average utilitarianism suggests that we should aim to maximize the average level of happiness in a population. In this context, the smaller population with much greater happiness per individual would be favored, as it would result in a higher average level of happiness.

 Prioritarianism, on the other hand, argues that we should prioritize improving the well-being of the worst-off individuals in society. This perspective also supports the smaller population with greater happiness per individual, as it would likely benefit those individuals who are experiencing the highest levels of suffering in the larger population.

 To further illustrate the dilemma, let's consider an example. Suppose we have World A, with a population of 10 billion people, each experiencing a happiness level of 5 out of 10. In World B, the population is reduced to 1 billion people, but each individual experiences a happiness level of 9 out of 10. According to total utilitarianism, World A would be preferable as it has a higher overall sum of happiness (50 billion) compared to World B (9 billion). However, from the perspective of average utilitarianism or prioritarianism, World B would be favored as it has a higher average happiness level or benefits the worst-off individuals.

 It is important to note that this thought experiment raises complex ethical questions without clear-cut answers. Different individuals may have varying intuitions and ethical frameworks that influence their decision. Additionally, empirical evidence and real-world examples may provide insights into the trade-offs between population size and individual happiness, but they cannot definitively resolve the ethical dilemma.

 In conclusion, the Repugnant Conclusion challenges us to grapple with the tension between maximizing overall well-being and the quality of individual lives. While total utilitarianism may support a larger population with lower happiness levels, alternative ethical frameworks like average utilitarianism and prioritarianism argue for prioritizing greater happiness per individual or improving the well-being of the worst-off. Ultimately, the choice between these two worlds depends on the ethical perspective one adopts and the weight they assign to different moral considerations.