Final answer:
People have used the concept of Limits to Growth to critique socialist ideologies, advocate for population control and resource conservation, and emphasize the potential of technological progress.
Step-by-step explanation:
According to Parenti, people have used the concept of Limits to Growth in several ways to support their arguments. One primary way is as a critique of socialist ideologies, suggesting that such systems may not account adequately for the finite nature of resources and the challenges of sustainable growth. Others have invoked the concept of limits to advocate for population control and resource conservation, arguing that an understanding of our planet's carrying capacity necessitates measures to prevent overpopulation and overconsumption leading to environmental degradation. Additionally, while not explicitly mentioned by Parenti, the concept of limits is sometimes used to emphasize the unlimited potential of technological progress, with the belief that human ingenuity will overcome any potential scarcity or limits to growth. Furthermore, it's important to clarify that limits have indeed been used to support various arguments and are not an unused concept.