Final answer:
Conclusion paragraphs should not introduce new details; they are meant to summarize and conclude the discussion, ensuring a sense of completeness.
Step-by-step explanation:
The conclusion paragraphs of an essay or written work are designed to summarize the main points, restate the thesis, and provide a final perspective on the topic. Introducing new details in the conclusion is often considered inappropriate because it can confuse the reader and leave the essay lacking a sense of completeness. In a well-structured conclusion, one should tie up loose ends and reinforce the arguments made, rather than adding new, unbuilt material.