Throughout the universe, can complex intelligence and consciousness only manifest itself via chemistry and brain, or is it possible for forms of life and intelligence to evolve in other ways, such as in the form of plasma within or on the surface of stars or even as a form of wave?

Strangely, this question relates to the concept of free will.

If you believe free will is an illusion then consciousness already exists all around us while we refuse to grant it validity. Allow me to explain.

First, lets presume consciousness has no magical property about it. Then it is data processing and usually cyclical. A data storage and retrieval system can have almost infinite forms. With the right interpreter, the locations and nature of the objects in your house could represent a complex data storage system holding vastly more information than is immediately apparent.

If we then notice that ideas themselves (sets of correlated data) behave like organisms in that they reproduce, mutate, and compete then it is easy to conceive of the idea of intellect emerging spontaneously. In fact if we ascribe the rational mechanistic view of the universe proposed by science, we must accept that consciousness is an inevitable consequence of complex physical system and will spontaneously emerge under competitive pressures, which are ubiquitous.

So why do I mention free will? The question that must be asked is if humans actually have free will or not. If we believe in the butterfly effect of chaos theory then every thought we have and every action we take is the inevitable consequence of a hyper-complex system of cause and effect.

At this point we have an argument of a random variable from indeterminacy but regardless of what set of pips the "die" lands on, there is still, unequivocally a causal chain that leads to thought and action. (filtered through genes and memes) It is our hubris alone that says that we made a decision.

We are forced to accept that free will is an illusion if we believe in a non-magical universe or if we insist upon free will must accept that we believe in magic.

For instance, I feel I choose to drive go to work in the morning but a butterfly flaps its wing in Japan and a subsequent rainstorm causes a car to hydroplane into me on my way there. While this is a hyper-simplified form it shows how any control over any moment is utterly illusory.

What does this have to do with differing mediums for consciousness? The question you must ask yourself in light of the fact that the configuration of molecules in water are in fact a system of data and the swirls that occur as they flow down a river along with their tendency to also remain together, are no different from the memory and processing which happen inside a human mind. So when a river moves a boulder, does it feel like it decided to do so? It's obvious that tiny little changes upstream altered every little change that the river makes to its environment but how is that different from our memories of experiences? How is the start of the river extremely different from instincts?

Water has electromagnetic properties. When a tree grows it adapts to availability of sunlight, winds, and the ground it grows from. It reacts to change and can heal scars. As the sap moves up and down through the seasons, how is that not processing memories? As the sap flows through old scars is a tree remembering old wounds?

If consciousness isn't magic and data can be stored in a variety of ways, then our knowledge of computing and electromagnetism along with what we know of the human brain leads to the inevitable conclusion that various types of consciousness must exist in a wide variety of places.

Or you can just believe that humans are god's special little snowflakes and only meat computers get souls...