Molecular assembly theory; a theory which helped Astro-biologists develop an index to search for life as we do, or do not, know it.
Link: https://astrobiology.nasa.gov/news/universal-life-detection-astrobiology-assembly-theory/

Astrobiology
Charting the Cosmos: the Concept of Kardashev Civilizations
As we gaze upon the universe, contemplating our place in its vast expanse, we grapple with questions about our future.