Not only methane, but CO2, urea, and a host of other compounds can arise from both organic and inorganic sources. And there are many thousands of organic compounds (found in living organisms or their decay products) which can be synthesized in the laboratory. For example: tetrahydrocannabinol!

For convenience, we loosely define things as "living" which are capable of metabolic activity, and self-replication. But where exactly you draw the line is strictly a matter of convenience, or if you prefer, convention. There are even intermediate forms. Viruses and prions, for example, are non-metabolic yet capable of reproduction, although they must first hijack a living cell's reproductive machinery in order to make copies of themselves. Otherwise, a virus isn't "alive" at all. Its simply a lipoprotein sheath surrounding a bit of dna. Some are so simple we know their structure and organization down to the last atom, and we could build them in the lab if we only had tools small enough to assemble the atoms correctly. Viruses are not only capable of reproducing by making exact copies of themselves, they can also evolve, by making variants of themselves.

Some forms of software are also capable or replicating themselves. Does that make them alive? And software isn't even composed of matter. Its strictly symbolic. You can send it over the telephone.

Vitalism died a long time ago. Living things are just more complicated than dead ones, there is no fundamental difference between the two. They differ in degree, but not in kind.

There is nothing special about "life". Its just a highly organized collection of chemical compounds. There's nothing special about the "soul" either. It's just a highly organized form of software, and there is no fundamental reason it couldn't execute on a machine as well as in an organic brain.

But that's a subject for another post.