Viruses are more like robots. They don't respond to stimuli. They just, do.
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 definition of "life" comes down to splitting hairs. We don't consider something "alive" if its behavior doesn't change when its environment does.
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).
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.
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".