While talking about the search for extraterrestrial life, you may notice the difficulty in drawing a line between the living and nonliving. Bacteria are considered life forms, but viruses are not. Artificial Intelligence is able to do a lot of things that human beings can do, but it is not viewed as life by the general public…so what is life after all?
According to our textbook, there are six key properties for life: order, reproduction, energy utilization, response to the environment, and evolutionary adaptation. Examining those properties, we can easily rule out some suspicious candidates: viruses don’t have orderly arranged molecules; Artificial Intelligence also do not have cell structures.
However, as biologists regard evolutionary adaptation as the most fundamental property, the definition of life can be simplified as “something that can reproduce and evolve through natural selection.” Under this definition, all physical entities that have self-sustaining processes can be called life. For example, Artificial Intelligence, which has been a popular topic in recent years, might be considered as “artificial life” that can reproduce and evolve in the form of codes.
Now that the definition of life has become more generalized, can we view AI as an advanced life form that has never appeared on Earth before? If we take this different point of view, is cell-based life only a part of the spectrum of life? Maybe we are just in a phase of Earth’s history that life with cell structures are dominant. Then, in the search for extraterrestrial life, what are we really looking for?