It's interesting that some microorganisms and maybe some fetuses make choices (@Christy) as it means they're selective and why they select what they select would be interesting to understand, in the case of fetuses because they become babies and adults and understanding their choices from an even earlier stage than now generally acknowledged would be interesting in understanding adults. It's an additional means of understanding the world around us. It might lead to more social interaction between fetus and mother, although in the first years or perhaps decades it would likely be haphazard and mostly meaningless to one party and ineffectual for both (that's part of a learning curve). For microorganisms, for those potentially helpful to humans we might want to learn how to encourage them to do what we want apart from breeding colonies through genetic selection and for those harmful to us we might want the additional tool of discouraging them, especially useful for any dual-use microorganisms that we don't want to destroy. But I'm not worried about practical applications for the knowledge now. Curiosity is a good enough ground for many investigations and analyses, including this one.
You wrote, "all pure, untestable speculation". Some; not all; it built on what is known of some microorganisms. Untestable, much of it, yes; we've had many as-yet-untestable hypotheses and some have eventually been proven wrong and others right and others remain unknown. Nothing wrong with figuring this out. The chemist's table of elements took known data and built a theory around it that was used to predict the discovery of elements with certain characteristics and that turned out to be correct. Much of Einstein's work was not proven until decades after he died. String theory, the last I heard, still is wanting for empirical proof and I read that Nobels are not granted without that.
As to fetuses, I made a list, mostly I think of signifieds that would be represented by noun-like symbols but some by verb-like symbols, some years ago and I might dig it up again soon. I think I included kicking as a possibiblity, but only as a possibility. Now, I was focusing on the principle of fetal choice.
You responded to my statement that "[b]y definition, without a signifier a potential signified cannot be a signified" with "[b]ut that has to do with communication, not thought. Concepts can exist mentally before they have words attached to them, before they can be communicated to others." I am indeed posting about communication, including intrafetal communication. A concept needs a symbol for both internal and external communication. Try to develop one example of a signified perceivable by a person but without a signifier.
Communication need not be only with others, as noted above. It can be with self and is useful for memory and prognostication.
From me: "Those are social interactions." Your response: "I don't think they really count. The mother is not responding to the baby." Yes, she is, even if only in the nearly minimal way of being assured that nothing bad happened due to her earlier transmission to the fetus. And if a sergeant says over an intercom that soldiers should stay where they are and then shuts off the intercom, we can still say that the sergeant communicated with the soldiers, even if the soldiers never in their lives talk to that sergeant and even if they disobey and go somewhere,, as long as the soldiers understood the sergeant's order.
You wrote, "Chomsky does not say that any actual language is hardwired into the brain . . . ." I didn't write that he said that. I wrote "part" in "the part of natural language that is biologically determined (see the work of Noam Chomsky et al.)".
Home heating systems (@Argon) probably don't make choices like you or I do, not even when controlled for complexity or speed of choice (for example, a common thermostat is designed to always turn heat on when the sensed temperature rises past a user-preset threshold and never otherwise, so that would be classified more as an automatic response and not as a choice); but you might want to argue for a device run by artificial intelligence as harder for me to counter. AI now has practical applications (IBM says it has reinvented itself around AI and its Watson system). AI is still developing by following what is being learned about how humans think. I'm not an expert on AI, but I don't think AI methodology other than speed has leapfrogged ahead of humans by much; computing often works in ways brains don't but usually with definite limitations brains have less of, so AI and cybernetics (which Norbert Weiner wrote on in the ca. 1950s) are mostly behind where human brains are. So I'm not sure I'd use even AI as a model for choice in biological systems.
Philosophically, some argue that no one exercises any choice, because the universe is wholly predeterminative, meaning the Big Bang's initial conditions determine what you and I do. If you're outraged and say so, that, too, might have been inevitable. I prefer to live as if we have choice. Whether laboratory scientists are wrong to understand choice as they do has largely been settled in their field even though some (not all) philosophers would disagree.
Much of what used to be in the realm of philosophy has moved into realms of science, with scientific method, and I prefer things that way. Much in philosophy is inconsistent.
Inanimate objects are definitely not microorganisms. I don't know whether microorganisms are composed partly of inanimate objects but I doubt they're composed entirely of them unless every atomic particle and energy quantum is an inanimate object, which would make the term "inanimate object" largely pointless to use in discourse about life. So, given how we usually use that term, I doubt that a microorganism is entirely composed of inanimate objects.
I don't and didn't doubt that nonchoice phenomena occur in organisms of any size. I accept, without looking, that the Yi-Huang-Simon-Doyle paper supports nonchoice. I've been posting about "some" microorganisms. Showing an example that is not choice does not disprove that choice exists in some other circumstances.
You certainly may disagree with any scientific paper and the thinking behind it; many people disagree with many entire fields. I'm not scientists' manager and issues with their fundaments should be taken up with them, as they can make warranted changes to their own papers. I wouldn't agree that choice is impossible or can't be found (if that's even your view), since we tend to find it in most humans.
@beaglelady: I'd leave that ("I guess we can claim that plants make choices also" and your vine making a choice) to (I think) botanists to verify. I wrote of some microoorganisms and some other organisms (e.g., people) as choice-makers. I didn't mention plants. If plants don't make choices, that says nothing about whether some microorganisms do.