It's easy to get wrapped up into discussions about words, but don't forget that the things they point to is what's really interesting.
Everyone has built up, over their lifetime, an implicit mental notion of "life", which is based upon the sorts of characteristics of things they classify as being alive. Many (I'd say most) people think this mental notion is some objective category that exists external to their mind, some thing that has a kind of essence that is shared by all the instances of life. They see the task of defining life as defining the essence of this category, and see there being an objective question as to whether something (e.g. a kind of virus) fits this category.
But this is to confuse a mental construct with what is out there. There are the objective properties of things like different types of viruses, different types of bacteria, of different types of mammals, and of all other natural phenomena. You can talk about what the similarities and differences are between the objective properties of a type of virus and a type of bacteria, for example, and there are simpler kinds of phenomena vs more complex ones, but there's no actual "life" category out there, separate from our mental constructs, to be objectively defined.
Even chemicals "evolve"
Sb trying to push sb else to use a definition meets the second part of the sentence.
This is post-modernism in thin disguise.
Certain categorizations can be more valuable (practical, useful, just, etc) than others, in which case it's reasonable to rally for their use over other, less valueable, categorizations.
To the second part: To one practical is to the other unpractical. To one just is to another unjust.
To push certain categories over others just says to me you want them to be in your frame(practical, useful for you I guess?).
And to not give an argument on the usefulness is to hide intention. But I'm not too firm on that yet.
It's most assuredly post-modernist because it implicitly assumes that all categories are equal in value (i.e.: that no category is better than another), and that the decision is at it's core a power-struggle (i.e.: oppressive to the loser).
This is, again, a tired and fruitless approach.
Before the discovery of these Giant Viruses as I guess we are calling them now, you used to be able to make a useful distinction between cellular-based life, and viruses. Viruses were mere packets of information as far as our best understanding went with very simple mechanics. Cells are more complex, with a useful distinction being made between prokaryotes and eukaryotes when necessary, but each could be easily identified as being made up of one or more cells.
As our understanding of life improves, so does our useful observations into that murky grey area between life and not-life, and I suspect we will have to potentially extend the definition of life but come up with a vocabulary that more usefully delimits the forms it can take from its most simplest forms into the murkier grey area where viruses start to resemble cell-based life.
Science is a work in progress, and so must be the scientific lexicon. Consider further your use of the word "die" and is that really the word you would use when a virus expires? Maybe, if you consider them to be alive in the first place, but you might use the word "destroy" if you considered them to be more like an object, or at least not alive.
We want to exclude viruses because they are too mechanical. There's no magic to them. That's the way it appeared before we started finding all these giant viruses anyways.
But the presence of a cell wall is a pretty significant feature nonetheless.
It's similar to how it's difficult to argue whether a data format is a programming language (Turing completeness is an obvious but unnecessary and insufficient distinction). "Declarative programming languages" muddy the waters but most people would agree that a JPEG image is just data whereas a PHP script is a program.
The definition of "life" comes down to splitting hairs. We don't consider something "alive" if its behavior doesn't change when its environment does.
The entire process of injecting their RNA is simply a chemical reaction to being attached to a receptor.
Basically, they just drift along until they hit a bacteria with the right receptor, then inject their genetic material and the empty hull is either discarded or simply continues to hang onto the cell.
The outer hull of the phage doesn't do a lot.
A virus is just a computer program that needs a Von Neumann machine (CPU) to run on. Following this analogy we could define alive by saying that the combination of a program and a Von Neumann machine makes the entity alive.
[0]: Let's not argue about whether it makes sense to say that abstract concepts also have a physical manifestation. Programs are concrete expressions encoded on a physical medium (whether using magnets, electrical charges or even the position of mechanical switches).
for a bacteria the most common response to environmental change is to die
I think this is too vague. A cat may continue to sleep without responding to changes in its environment but may respond to an internal stimulus (hunger) and get up and go. So response or lack of response to the environment may not be a good criterion to define life.
Anyway, the term "life" is poorly and inconsistently defined and really only means "what we generally think of as life".
https://www.cliffsnotes.com/cliffsnotes/subjects/sciences/wh...