What is the Purpose?

[Neo-Scholastic]

No, I am attributing teleology to the whole-system of the bacterium, which is greater than the sum of its chemical parts.

Keyword: attributing. Once you start to talk about emergent properties, you've already given up the game. You cease talking about physical properties and begin discussing mental ones. This is a problem because you can now start assigning mental properties to anything you want. "My thermostat wants to reach 72 degrees."

You seem to be very hung up on things like chemistry and extreme reductionism.

Guilty as charged. Physical reductionism is a pernicious and common belief among AF members. I doubt that many fully understand the logical conclusions of this belief.

OK, instead of a bacterium, let's talk about the ghost
of a bacterium, it's beautiful sparkly little soul. Now that there's no nasty chemistry involved, how does this change anything? How are we now suddenly able to talk about purpose and intention and "about-ability"

Now you have posited the existence of a non-physical entity already endowed with mental properties like intention. That's hardly comparable with an actual physical process.

In a Universe with such an entity, everything is necessarily deterministic (or predestined, if you prefer that term).

That is only one doctrine. I have a different view.

You're mis-applying reductionism. A tire can't drive anybody anywhere. Therefore, there can't be such things as cars, unless "driving" is defined as a supernatural act.

Not at all. I try to maintain a clear distinction between identifiable physical processes and descriptions made in terms of mental properties. I think far too many people blurr that distinction with ambiguois ideas like emergence as if that somehow bridges the Cartesian divide.

As far as I can tell, teleological operations are substrate-invariant. If a particular calculation is performed using the beads of an abacus, the gears and cams of a Babbage machine...

Kudos for mentioning Babbage machines. You prove my point. The beads of an abacus have no meaning in and of themselves. An intelligent agent must assign the meaning of '1' to some beads and the value of '5' to others. Not to mention the order of magnitude represented by each column. The abacus itself has no meaning.