I suspect we all share a pretty similar understanding of the word "organism." So the disconnect must be in the word "cybernetic" and its association with organisms.
Folks can look up definitions of Norbert Wiener's coinage of the word "cybernetic" for themselves, but here's a quick take on it. The way we think of the word today is something like "computerized mechanism." The word "electromechanical" is close to this, but doesn't quite capture the notion of adaptive electronics governing the mechanical bits. A cybernetic device uses computer processing to receive I/O from the mechanical part, does some planning and decision-making based on that data, then responds with some appropriate control signals which tell the mechanism how to behave. So a cybernetic device isn't just a mechanical device; it's a mechanical device with some intelligence that conditions its operation, resulting in adaptive behavior in a real-world environment.
The point of this -- and what Wiener was interested in -- was the creation of feedback loops. The actions of the system produce effects on the environment, information about which is then looped back into the system to generate the next set of actions. Depending on how you program the control elements of the system (the bits that determine whether the system uses negative feedback, positive feedback, or some combination of both), you can get some really interesting behaviors out of a system.
So that's "cybernetic." But the association of the word with "organism" matters, too. To say that something is a "cybernetic organism" is to observe that the organism is made distinct from other similar organisms by the installation of a cybernetic element or elements. A "cybernetic organism" is an organism that is distinctive because of its cybernetic elements.
What this suggests is that to qualify as a cybernetic organism, the cybernetic part should be something that's not merely strapped on but is so deeply integrated into the organism that the combination is a new kind of thing. It's not just a cybernetic device, nor is it just an organism; it is a new kind of thing we can call a cybernetic organism, or cyborg for short.
By these definitions, then, we can start to see something like a spectrum with the purely biological at one end, the purely electromechanical at the other end, and the cyborg somewhere in the middle. Let's consider just human organisms:
- Someone who wears glasses or contact lenses is not a cyborg -- those aren't cybernetic devices, and they're not integrated into the organism.
- Someone who wears a simple prosthetic (like a wooden leg) is not a cyborg -- those aren't cybernetic devices, and they're not integrated into the organism.
- Someone who's had corneal replacement or who's had a lens inserted into their eye is not really a cyborg -- although those devices are integrated into the system, they're not cybernetic.
- Someone who wears a relatively advanced prosthetic like a Boston arm is not quite a cyborg -- these prosthetics are worn (electrode are attached to the skin) and can be removed, so they're not fully integrated with the person.
- Someone with a device that is permanently attached through surgery and whose inputs come directly from nerve endings, such as a pacemaker, a cochlear implant, or an advanced prosthetic limb, would be a primitive form of cyborg, since the device operates through feedback and, although it could theoretically be removed, it is normally deeply integrated with the person.
- Someone with multiple deeply and permanently integrated cybernetic devices that replace or extend lost functions or add new functions is definitely a cyborg.
If they're just mechanical springs, or if they're just clamped on externally, then she's not a cyborg.
If however they're more than just mechanical springs -- that is, if they've got some built-in computer-based sensing/processing capability -- and if they're pretty much permanently integrated into Chell's legs, then yes -- she's a cyborg.
If Valve disagrees, it might be worthwhile to hear their definition of "cyborg."
So how's that for analytical overkill? :)