It seems to me you confused by overlap in meaning of word “state”.
In this context, it is “state of target of inquiry”—water either changes its solid form by melting or not. So state refers to difference between “yes, waters changes its solid form by melting” and “no, waters does not change its solid form by melting”. Those are your 2 possible states, and water itself having unrelated set of states(solid/liquid/gas) to be in is just coincidence.
It seems to me you confused by overlap in meaning of word “state”.
In this context, it is “state of target of inquiry”—water either changes its solid form by melting or not. So state refers to difference between “yes, waters changes its solid form by melting” and “no, waters does not change its solid form by melting”. Those are your 2 possible states, and water itself having unrelated set of states(solid/liquid/gas) to be in is just coincidence.
Thank you, your explanation of state made it easier for me to understand the meaning.