TL:DR: According to the perspective-based argument (PBA), scientific objectivity should be based on metaperspective reasoning rather than reasoning from an imaginary impartial perspective. Therefore we should be wary of theories describing the world from a god’s eye view, e.g. Bohmian mechanics.
It is uncontroversial to say scientific theories should be objective, or in some sense perspective invariant. As discussed in section 2.1, there are two possible ways to achieve this within the PBA framework. The purpose of this page is to compare these two methods.
First is the Imaginary Impartial Perspective (IIP) approach. Which states in order to be objective, we should give up our individual perspectives and reason as an imaginary impartial observer. Or metaphorically speaking, think as an outsider, or take a god’s eye view. Since the perspective center is imagined, it is uninvolving. It resembles the “view from nowhere” analogy in traditional reasoning. Only according to PBA, this “view” cannot be really aperspectival. Instead, it is from a detached fictional standpoint.
The other approach is to recognize the critical role of our first-person perspectives. While also accept reasoning from other perspectives being as valid as my own. Then analyze reasonings from multiple perspectives to abstract theories applicable to all and rejecting idiosyncratic notions (e.g. the special status of indexicals from each perspective). It is the reasoning about perspective reasonings. I called it Metaperspective(MP) objectivity.
I argue perspective-based reasoning should consider MP superior to IIP due to 2 reasons. First, MP is more parsimonious in terms of assumptions. Second, MP based theories have more historical success.
Why Is MP Superior
No matter which approach one prefers he has to start with observations bounded by his own perspective, then also take observations from other perspectives into consideration. From here, IIP goes further to postulate there are elements of reality separable from perspectives. It then goes on to directly present this reality from a detached viewpoint. In contrast, MP makes no such assumptions. MP theories are not direct presentations of reality but hypotheses generally applicable to individual perspectives’ observations. The actual descriptions of the world need to be done from these perspectives.
Despite their significant difference, most scientific theories are ambivalent toward these approaches. Take the second law of thermodynamics as an example (that entropy of an isolated system keeps increasing). It can be regarded as a direct description of the world, or be regarded as an indirect description of observations from any given perspective.
However, some theories are only compatible with the MP approach. The most obvious one is relativity. Without an absolute reference frame, there is no way to directly describe spacetime from a detached viewpoint in purely objective terms. Such a description is only meaningful from a given perspective. Relativity can be seen as the rules of spacetime’s behavior generally applicable to any perspective, in which no preferred godlike viewpoint exists.
In contrast, I cannot think of any commonly accepted theory that only works with the IIP approach. I think this is not coincidental since the MP makes weaker claims.
Back to Quantum Interpretations
Bohmian mechanics is another famous quantum interpretation. It proposes the existence of pilot waves which is non-observable by nature (hidden variable). So part of reality is inaccessible to any particular perspectives, which need to be described from the disengaged god’s eye view. As expected, it does not make references to “observers” as opposed to orthodox interpretations. In principle, Bohmian mechanics need to be used from an outsider perspective, or disregarding PBA, in purely aperspectival objective terms.
Based on the above Bohmian mechanics is a strictly IIP theory. This is why I don’t think it is the correct interpretation. Also why I am pessimistic that a convincing relativistic version of Bohmian mechanics can ever be developed. Because as its exact opposite, relativity is a strictly MP theory. The two are inherently at odds with each other. Bohmian mechanics exclusively uses the god’s eye view while relativity is against the idea of a preferred perspective.
Objective collapse, such as the GRW theory, is another school of quantum interpretations. It proposes wave function collapse as naturally occurring phenomena. This removes the necessity of “observers” in quantum mechanics, making the theory IIP compatible. However, comparing to Bohmian mechanics, these collapse events are observable. So in principle at least, they can still be interpreted by the MP approach.
However, this ambivalence comes at a cost. They added additional variables, such as the low probability of spontaneous collapse. These variables are undeniably ad hoc. I think there is no good reason to do so just to make quantum mechanics IIP compatible since MP is the correct way. The good thing about objective collapse theories is that they are experimentally testable, at least in theory. I think the prudent way is to not believe in these ad hoc processes until experiments confirm their existence. Honestly speaking though, I personally don’t believe they ever will be confirmed.