Photosynthesis rebuttals
Back to the topic of photosynthesis, I have a final set of rebuttals against the concept of photosynthesis. Basically, it boils down to "photosynthesis" not explaining anything, being redundant to existing lore, and offering no practical applications for the games.
"Photosynthesis" does not explain anything
Protoss photosynthesis seemingly originated from a Q&A sometime in 2006 or so. Someone asked “how do protoss eat without mouths?” and a PR person answered “photosynthesis, like plants.” Both the question and the answer are founded on ignorance.
The SC1 manual already said the Protoss were hunters, so presumably they ate in some alien fashion. The answer is ignorant not only of the previous lore but of real science, as
game theory places autotrophic animals at a massive disadvantage outside exceeding rare conditions.
The photosynthesis explanation does not really answer the question it was intended to. The questioner would have no understanding of photosynthesis and if they did then they would dismiss the answer as ignorant. The answer might as well have been “they just do, I don’t need to explain it” for all the difference that it makes. Even “psychic vampirism” or “pylons” would have been a better answer, since that would have been consistent with the existing setting without introducing unnecessary trivia.
It simply does not make sense from a scientific perspective and any attempts to explain it only raise more questions like “how does it work?” “how is it more efficient than terrestrial plants?” “how does it provide nutrients?” and so on. Whenever someone wonders how it is possible without resorting to pseudoscience and magic that doesn’t actually answer anything, the answer ultimately boils down to “they just do, I don’t need to explain it.” That is same answer I suggested for the original question. We are back at square one.
There is simply no point to saying “photosynthesis.” It doesn’t explain anything better than “they just do,” which it ultimately boils down to by itself since there is no science to support it. The protoss may not have mouths on their faces, but we can assume they eat in some alien fashion and we don’t need any over-complicated physics-defying explanations how.
"Photosynthesis" is redundant to the existing Psi mechanic
The original lore outright stated that Protoss buildings and units already get their energy from pylons, connected to the Psi Matrix, in the form of psionic energy or Psi. The Psi mechanic exists as a counterpart to Supply for Terrans. Psi may be assumed to operate on similar principles to Supply, serving as an abstraction of electricity, food, shelter, ammunition, etc. If Protoss already get sustenance through this system, they do not need to be photosynthetic on top of that.
"Photosynthesis" offers no practical applications
The previous lore already stated Protoss were hunters. What do we gain by changing that to photosynthesis? It adds nothing of value either in comparison or on its own merits. With the Zerg, their genetic engineering gave us their overall motivations and behavior, the gruesome backstories about the creation of ultralisk and overseer, as well as the evolution missions in HotS. For the Protoss, the fact that they photosynthesize is completely irrelevant. They do not behave any differently than humans do, even though autotrophy would logically be expected to render their psychology unrecognizable to us. The games certainly never reference photosynthesis nor do anything with it in their gimmicks. How would you even make a gimmick, much less a compelling one, about protoss photosynthesis?