Why not consider it alive? The same with the fires mentioned in other comments. In The Andromeda Strain (the novel, don't remember if it's in the film as well

Why not consider it alive? The same with the fires mentioned in other comments. In The Andromeda Strain (the novel, don't remember if it's in the film as well), there's a scene where the characters are trying to determine a single quality they can look for that signifies life. They come up with energy conversion, and they do consider luminescent watch hands and geologic formations. It's been a long time since I read it, I don't recall them ending with back-patting and "mission accomplished" cheers, but the point of the scene wasn't to make a definite answer for the readers nor the characters - it was that when you're looking for life, perhaps your definition of "life" will need expanded. So why do we need a definition that absolutely includes This, and absolutely excludes That and The Other? What if we settle on a definition and found out it does apply to The Other, why must we change the definition instead of changing how we categorize The Other? Both are adjusting our model to fit new evidence. Why be so determined that Life Must Be Like Us And No Other?