It's not impossible that life might exist based on other foundations than the ones we've witnessed, but there is some compelling evidence that carbon based life should be the more common form. Firstly, carbon based chemistry is far and away richer than any other type of chemistry, there are an essentially infinite number of different carbon based compounds, and they span an enormous array of properties and chemical activities. Secondly, the raw ingredients for those chemicals are extremely common throughout the Universe. Moreover, natural processes produce the basic building blocks of life routinely.
Additionally, we see from the history on Earth that almost as soon as conditions suitable for life to exist came into being then it wasn't long before life started. It's difficult to draw conclusions from just one data point but that may indicate that the process of biogenesis is fairly straightforward, under the right conditions.
The bias towards focusing on carbon based life comes because the route to such life seems straightforward, and makes use of abundant naturally occurring compounds, while at the same time we have not even the slightest hint of how naturally occurring non-carbon-based life would even be possible.
Additionally, we see from the history on Earth that almost as soon as conditions suitable for life to exist came into being then it wasn't long before life started. It's difficult to draw conclusions from just one data point but that may indicate that the process of biogenesis is fairly straightforward, under the right conditions.
The bias towards focusing on carbon based life comes because the route to such life seems straightforward, and makes use of abundant naturally occurring compounds, while at the same time we have not even the slightest hint of how naturally occurring non-carbon-based life would even be possible.