Should we always do subjectively once we worked out what we ought to do objectively?

This Monday I’ve visited a one-day conference at the University of Cambridge on Non Categorical Thought and I’ve found it fantastic, both the people and the content and the quality of the discussion. You can read abstracts here.

There was one change in the programme, the first talk was given by Arif Ahmed instead of Peter Hawke, and the title was Evidentialism and Objective Value. It was a great talk, accompanied by a professional hand-out to make the argument easier to absorb. I’m not going to spoil Arif’s argument but only discuss one comment of mine I made at the end of the talk related to a premise of the main argument that seems indisputable according to Arif.

This premise is the following:

If you know that you objectively ought to do something then you subjectively ought to do it.

Arif Ahmed, Evidentialism and Objective Value, conference hand-out

Let’s call this principle – I’m pretty sure there’s a name for it in the literature, but I don’t know it – the ‘Informed OS Transition’ principle for reference’s sake, where OS is a shorthand for ‘from Objective Ought-to-Subjective Ought’. Sorry, I know it sounds ugly and terribly technical. It is coming from my stem cell biologist past where we have the concept of the epithelial-mesenchymal transition (EMT) about cells changing their phenotypes due to different triggers.

Little elaboration on the principle citing the hand-out:

Schematically: what you objectively ought to do is what you subjectively ought to do if you knew all the relevant facts. The subjective ought makes allowances for the subject’s ignorance and only for that.

Arif Ahmed, Evidentialism and Objective Value, conference hand-out

Arif here is referencing Michael J. Zimmerman, 2008: Living with Uncertainty. CUP concerning the ignorance restriction.

Let’ see my little thought experiment I mentioned in my comment at the end of Arif’s talk that might provide an argument against the ‘Informed OS Transition’ principle that seemed indestructible.
Imagine a world where every individual (or just one individual ‘A’) has an objective twin, a sidekick, a bodyguard, a shadow, a clone (?), a copycat machine (?), called ‘B’ who’s there with them (using singular they instead of she/he from now on) and who is capable to act according to the ‘Informed OS Transition’ principle all the time in case of all morally challenging incidents, so capable to make the well informed objective -> subjective transition and act accordingly, committing to objective ought. 
Here comes the twist: In that world person ‘A’ can be seemingly morally lazy, can act sub-optimally, or can do nothing knowing that ‘B’ is there with them and will act according to ‘Informed OS Transition’ principle. So ‘A’ has a way of delegating the agency required by the ‘Informed OS Transition’ principle to ‘B’ while avoiding to personally act according to ‘Informed OS Transition’ principle by themselves. 

The question is whether such a counterfactual scenario is relevant in terms of evaluating and potentially restricting the truth of the ‘Informed OS Transition’ principle when it is used as a premise in arguments in moral philosophy?

I’m deeply ambivalent (puzzled) concerning the relevance of such a scenario but in philosophy philosophers are explicitly trained to critically challenge principles that seem indisputable even if those challenges might lead to ‘ugly’ positions they are not personally comfortable with.

One might think perhaps that this way (according to the objective twin scenario) of complying with ‘Informed OS Transition’ principle and not complying with it at the same time through a dubious version of hierarchical double agency (double-act) does not challenge the relevance of acting according to ‘Informed OS Transition’ principle yet still it seems like an imaginable logical possibility that needs be addressed in the context and scope of the truth content of ‘Informed OS Transition’ principle. But I’ve only gotten so far in thinking about this and would really appreciate your further insights at this point.