Why can’t we live without water?

Water is the solvent of life.

Metabolic and homeostatic systems need something like water to function. It’s polar and so good for holding and transporting ions and proteins, is of a balanced pH and so a good buffer, it’s self-cohesive and so consistent and gradient, has high heat capacity and so a good thermoregulator, and is abundant on Earth in a liquid state and so easily accessed and constituted.


We would need a replacement to keep life in solution and stasis. Nothing would substitute that we can tolerate, let alone allow us to be such dynamic organisms. It would require great modification to our biochemistry – or we’d have to upload to a quantum computer – to survive anhydrously. It can easily be argued life evolved on the basis of H2O chemistry.


  1. I’ve read that ammonia might work as a substitute for water in some sort of alien biochemistry, though only on planets where water is not so readily available as it is on Earth.

    Liked by 1 person

    1. It couldn’t spontaneously replace it, but given an ammonia world with organic molecules, it could be a chemical basis for life. Compared to water, ammonia evaporates at lower temperatures, isn’t as cohesive, and is liable to bond to molecules rather than just dissolved them. Nonetheless, it’s perfectly plausible ammonia life is out there in some form.

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