Of course, by this definition, societies and civilizations would qualify for being alive, but in my opinion, they are.

Plans are just that plans. Plans are the back-up, there is the surprise factor that only nature controls.

Joining the prestigious company of Steven Pinker. Since you publicly state your wish not to have children, I suppose it’s fair to ask what the reasons for it are. Consider that you are, compared to most people, in a much better position to have children. Also, there are many successful cosmologists (Barrow, Hawking, Sciama, Peebles—probably many more, but I don’t always know how many children people have) who have many children.

The question is whether I am alive, not my cells.

Well, if you want to draw that sort of distinction, we first have to decide whether “you” even exist in the first place…

However, a naturally occurring living organism must be able to reproduce. Otherwise, it would have no way to evolve and may as well not be alive if you are looking at it through an evolutionary timeline.

It’s the evolution of structure through time.

I disagree–at a minimum an information-based approach demonstrates that the biologist’s definition is best seen as a special case of a broader phenomenon than would be traditionally considered biological. For example, let’s just pick on some innocuous little words in the biologist’s definition. For example, “many.” Hmmm — is it the next generation? Some arbitrary (i.e., observer dependent) number of generations, or is it unbounded? Seems kind of important to specify or “fitness” has no real meaning. And then there is “population,” which does not necessarily need to be biological as originally intended by biologists (e.g., memes per Dawkins).

@ Steve Flinn:

Yes, but that the genome is decreasing its mutational Kolmogorov complexity by environmental selection by way of channeling Shannon information is known. Nothing that is described by considering the informational properties of the genome learning process is added to a biologist’s definition of the evolutionary process:

“Evolution is a process that results in heritable changes in a population spread over many generations.”

The pity description is “[a process of] differential reproduction”. Both of these are more directly informative of the biology entities and the biological process which is under consideration.

@ George:

Anyone can define out viruses. But mind that it now seems, with more sequencing, that many (but not all) viruses were once cellular life forms.

For example, eukaryotes such as amoeba, or even humans in some cases of lung inflammation, is beset by Megavirus. This newly proposed clade includes such large viruses as Mimiviruses, and have an argued signature of eukaryote ancestry.

Similarly mass sequencing has discovered virus genomes with archaean relations, and same goes for bacteria I think.

The proposed ancestry is that an early eukaryote, perhaps still un-nucleated, went parasitic, simplified and its only descendants survived as a virus. A related proposal is based on noting that they grow a “virus factory” inside a host cell that is as complex as some bacteria, that look for all practical purposes like a cell and uses some proprietary metabolic genes. Hence the viral factory is the mature individual and the virions (viral particles) the eggs.

Now the question for a definition of viruses as non-life is when exactly did the megaviruses loose their “life” property? They are rooted in life, they still look and act like cells. The only difference if the above proposals are accepted is that parasite simplification has made them loose, not the mouth and guts like a tape worm, but the egg metabolism.

If tape worms are bilaterians (which all have an ancestral digestive system), why can’t such viruses be life? (They probably have to be, if you ask an eager cladist.)