When they hallucinate, they don't do it consistently, so one option is running the same query through multiple times (with different "expert" base prompts), or through different LLMs and then rejecting it as "I don't know" if there's too much disagreement between them. The Q* approach is similar, but baked in. This should dramatically reduce hallucinations.
Edit: added bit about different experts
The question doesn't even make sense. You have to redefine it to "purpose" or some other word to even get started. The only literal interpretation is "what does 'life' mean?", which is just something like "a metabolic system capable of Darwinian evolution".