Is a paper a statement of personal belief (disagree with PI's writeup)? EDIT: My field is cognitive science &lt;- vagueness reflects broadness of subject area from social science through to basic neuroscience

Let's say some collaborators disagree on the interpretation and writeup for publication of their joint work. The rose-tinted solution usually offered is "talk it out and reach consensus".

Let's say one of the pair both is much more powerful than the other, and has no inclination to compromise. What then is the junior collaborator to do?

The fact there are not David and Goliath spats erupting constantly between PIs and PhDs/postdocs everywhere must be because

a) the situation has simply never occurred, juniors miraculously always agree with seniors, or
b) the situation has always resolved with consensus, PIs are always selfless, open and flexible, or
c) juniors capitulate silently, recognising both the necessity of conforming for their own immediate career and the apparent expectation of standing 100% behind something you had &lt;&lt;100% control over producing

It's the latter (italics) that I'm especially interested in and it marks the distinction between this junior scientists' dilemma and the ubiquitous "following stupid instructions angst" that all workers have.

In the non-academic working world the very practical and adequate solution usually offered is to state your concerns in writing and then meet the superior's demands to the best of your ability anyway. The goal is to distance oneself from the bad outcomes of the work by documenting one's own prior expression of misgivings, while respecting the chain of command. A further buffer against culpability for things imposed lies in the product of your work usually being "owned" by the company, not you / your reputation personally.

So somebody senior can make you produce a stupid product for the company to sell, and it is common (if not expected) that you might not have control over the final design, but you can critique and offer improvements, and if they're in writing you can point to them when nobody buys the crappy product. "I followed orders and I said this would happen".

The dilemma exists just the same for junior researchers - they get told to produce things and operate under a huge power differential. But they cannot disown what is produced in the same way. I have never seen a junior in a presentation come out and state "the experiment, collection and analysis was mine and is great, but this theoretical interpretation has nothing to do with me, take it up with my PI", for example. I suspect it would shock the audience because the culture is that every author backs every word of their collaborative output in a form of collective responsibility.

My question then is how can that collective responsibility be legitimate given the widely differing power between collaborators (especially the PI - PhD/postdoc relationship)? Is there some normative "out" that I've missed for the junior? Because if I'm right that (c) above is what happens, that means a big part of most juniors' induction into science is this coercion into complementing the emperor's new clothes.
It's a tough dynamic and there aren't universal rules. I'm not sure how to answer the original question because 'legitimate' isn't defined and the text rambles.

The central issue remains: how do varying opinions add up to a shared compromising publication in situations of unequal power? That describes almost every collaborative paper. There are many resolutions, including changing your mind based on new information. The bottom line is:

The shared paper requires compromise, and PIs have more power. Some of that asymmetry is appropriate and helpful to junior colleagues in the long-term. Some is not. If you're not comfortable adding your name to the best compromise you can find, then take yourself off the paper or don't publish it.

Also see: Can co-authors disagree in their own paper?