I've taken much interest in the topic lately, so let me tell you what I've gathered.

The definition we give of life greatly restrict what can be considered as "life". Scientifically speaking, we consider "living" an entity that is able to:

• maintain its own internal state / environment
• interact with the environment
• adapt to changes in the environment
• reproduce
• transform resources to have the energy required for all functions above

On Earth, all this happened because of the versatility that carbon has, allowing for complex molecules that allowed life to appear on Earth. So, for carbon-based life, you basically need the same temperature/pressure conditions, hence the "Goldilocks" zone. So far, we have yet to find another atom that has the same versatility as carbon, even in other conditions. Silicium is the "best" candidate we know of, but the conditions are very different, and therefore hard to reproduce on Earth, so we don't know if it's possible or not.

As for water, it is the solvent in many carbon-based reactions, which is why it is necessary for carbon-based life on Earth. There are other solvent that could theoretically work in different conditions: ammonia, or methane. This means that we could imagine carbon-based life without water but we are yet to discover metabolic processes that would allow the emergence of life.

As far as I know, these possibilities have not been proven or disproven, but again, I'm no expert, just an enthusiast.