In transhumanist settings the "posthuman" is a positive ideal. Humanity is being cast away and replaced by something better. Doesn't sound like a cyber zombie to me. Transhumanist settings and cyberpunk settings share a lot of window dressing, but the underlying philosophy is different.
The transhumanist posthuman is an ascendant being made better through tech.
The cyberpunk transhuman has thrown away his humanity for a lonely crib and diminishing returns.
In other words the issue isn't "other than human", that's a common trait to both genres, it's whether that "other" is an improvement over the original model.
I haven't forgotten. I'm just pointing out that the SR version of "posthuman" isn't exactly the transhumanist model.
In the immortal words of a great man from the 80's,
"I don't think that word means what you think it means."
1. Cyberpunk isn't a philosophy, it's a genre of science fiction.
2. Transhumanism is the improvement of a basic humans' capabilities through technology, technically, almost all cyberpunk literature and games fall into this category.
The edit-Cyberpunk genre is defined in a distopian, noir setting that puts basic human flaws in the spotlight. Things like the seven deadly sins, greed, lust, gluttony, envy, wrath and sloth, and how those qualities are essentially unchanged by the technology around them. Usually the antagonist embodies these negative qualities, while the protagonist only has one or two of them.
3. Post-humanism is becoming something other than human through technology.
If you've read Charles Stross, his 'Vile Offspring' of humanity (Accelerando) are Post-Humans, technically the Cyber-Psychos of the Cyberpunk 2020 game are Post Humans as well. These types of individuals and beings are exceptionally hard to write due to us, as humans, not being able to successfully write something from the perspective of a human/AI mental amalgamation of code processes running on a diamond core server in the non-elliptical plane of the solar system on self-replicating computers. We can imagine that it exists though. Just like irrational numbers and those people who believe crop circles are really done by Led Zeppelin's guitarist whilst he plays 'Stairway to Heaven' on a kazoo.
When you say the Transhuman posthuman you're kind of confusing two separate things.
The definition of a posthuman is this
"According to transhumanist thinkers, a posthuman is a hypothetical future being "whose basic capacities so radically exceed those of present humans as to be no longer unambiguously human by our current standards."link
http://en.wikipedia.org/wiki/Posthuman#Posthuman_in_posthumanismWhich taken literally, would apply to some of Shadowruns Metahumanity, because genetically they aren't 'human' strictly speaking. However, they are characterized as human in the literature and game books so in the end they don't qualify as Post Human.
The definition of a Transhuman is this
"Transhuman or trans-human is an intermediary form between the human and the hypothetical posthuman"link
http://en.wikipedia.org/wiki/TranshumanThe difference of those two concepts, to me, is the same as the difference between a lightning bug, and lightning.