We can make some progress on these issues by clearly distinguishing between investigation into the manifest image and investigation into the scientific image. With this in mind, we have set forth for us three main goals, with related subgoals, as follows.

G1. Achieving a better understanding of the manifest image, by focusing on:

(G1a) properties and relations; we plan to support the hybrid view and a specific approach to differential application.

(G1b) Time; we wish to construct a precise map of its commonsensical conception and clarify tenseless predication.

(G1c) The informal logic; we wish to shed further light on which principles it implicitly accepts.

G2. Getting a clearer grasp of the scientific image, by concentrating on:

(G2a) scientific realist commitments to properties, relations and unobservables; we wish to investigate whether and to which extent they can be taken seriously, despite instrumentalist criticisms, and the selective realist idea that our theories could be only partially true.

(G2b) Time; we shall investigate whether there is still room for presentism or dynamic conceptions of time in current physics, how the arrow of time must be understood in physical terms, and whether spacetime may be non-fundamental.

(G2c) Logical systems that grant consistency by circumscribing in various ways principles that appear to be accepted in the informal logic, such as those for truth and predication or laws of classical logic.

G3. Investigating how the two images must be related for them to be compatible at both (G3a) the metaphysical, and (G3b) the logical level.

We shall pursue these goals by parallel and mutually interacting inquiries, via the typical methodologies of the relevant disciplines, such as history, philosophy and metaphysics of science, analytic ontology, philosophy of language, linguistics and logic.

As regards G1, we shall also seek help from experimental philosophy. More details on G1 and G2 will be offered in Project Development. Here we shall focus on G3.

G3a (metaphysical level). We shall explore two (possibly complementary) strategies for the reconciliation of the two images, both emerging from the debate on scientific realism.

The first one relies on the “divide and conquer” imperative of selective realism: we wish to carefully discuss the criteria of realist commitment (Peters 2014), in order to see whether they allow for the exclusion of the components incompatible with the manifest image in principle and always, or sometimes and de facto.

Conversely, the desirability of avoiding any assumption conflicting with the manifest image may become a constraint on such criteria: selective realists should avoid commitment to any assumption that defies all attempts of reconciliation with the manifest image (including, of course, attempts to show that the manifest image is simply wrong in a particular instance at hand).

The second strategy follows Sellars’ Kantian perspective, according to which the manifest world is that of phenomena (how things appear to us through the senses), whereas the scientific world is that of noumena, “things in themselves” which science enable us to uncover.

In order to explore this hypothesis, we shall turn to analytic ontology and the metaphysics of science in asking questions such as these: if commonsense medium-size objects are only appearances of scientific objects, or the outcome of the interaction between scientific objects and our sense organs, should we say that they don’t exist really? Or that they exist after all, since they are identical to scientific objects? Does the scientific world grounds, constitutes or causes the manifest one?

By relying inter alia on the exploration of case studies from the history of science, we plan to argue that, whatever the answers to these questions, the scientific image aims at explaining the manifest image, and, conversely, the manifest image provides the heuristic premise and an abductive justification for the scientific one.

In this perspective, the two images can be reconciled if science is able to deduce the manifest image from its account of reality in itself (including the scientific description of our cognitive apparatus and of how external reality affects it).

In particular, consider science that describes reality in a way conflicting with common sense or as different from the way it appears to us (e.g., time as relative, particles as entangled, empty space with sparsely scattered electric charges appearing as a solid entity, wide collections of uncolored particles appearing as colored objects).

In such cases, with the aid of relevant background knowledge from physics, neurophysiology and psychology, science should also be able to explain why reality appears paradoxical or different from what it is in itself.

Similarly, when a theory postulates entities that cannot be observed, or can be but only in very indirect ways, it should provide a good explanation of why this is the case.

This perspective may issue useful feedbacks on which ontological commitments should be acknowledged, for without this explanation, it may be reasonable to suspend judgment on the existence of such entities (Angelucci & Fano 2009).

G3.b (logical level). Some of the above mentioned anti-Tarskian and anti-Russellian approaches can be seen as presenting the circumscribed versions of the prima facie valid principles as capturing principles of the implicitly accepted informal logic. When so viewed, these proposals pursue SM-compatibility. For instance, the revision theory of truth and predication (Gupta & Belnap 1993, Orilia 2000) and dialetheism (Priest 2006) can be seen in this manner.

However, there are serious problems with this line. First, the number of contrasting proposals of this sort is very large (Cantini & Bruni 2017, §6), and it is hard to understand how there can be such radical disagreements among the experts about the ultimate nature of the underlying informal system.

Second, although this claim had better be tested, it seems that ordinary reasoners are deeply committed to all the prima facie principles that are sacrificed in one or the other of these proposals; and thus it is difficult to admit that some of them are not really included in the informal logic.

In the light of these difficulties, we would like to explore in detail an approach sketched in Orilia (2014), according to which all, or at least a significant part, of the principles of the informal logic are accepted as default principles.

We plan to put this on firmer formal grounds, by recourse to Batens’ (1999) adaptive logic approach. This provides a way of taking advantage of a theory even if inconsistent, by distinguishing a paraconsistent fully reliable base logic, and an upper level logic, typically identified with classical logic. The rules of the latter lead to conclusions that may later be retracted.

We wish to take as upper level logic not just classical logic, but also naïve principles of truth and predication, and at the same time explore various small or even empty sets of rules as base logic (Goal G2c may be relevant here too, because it may indicate interesting ways of identifying the base logic).

Since the upper level logic should not be viewed as necessarily truth-preserving, this approach requires a reconsideration of the very notion of deductive reasoning, which we plan to back up with an accurate investigation of the notion of rigorous argument and of its historical evolution.

References

Angelucci A. & Fano V. 2009, “On What there Really is. Empirical Realism between Physics and Psychology,” Teorie e modelli 13: 105-118.

Batens. D. 1999, “Inconsistency-adaptive logics,” In E. Orlowska, ed., Logic at Work, Springer.

Cantini A. & Bruni R. 2017, "Paradoxes and Contemporary Logic,” Stanford Enc. of Phil., https://plato.stanford.edu/archives/fall2017/entries/paradoxes-contemporary-logic/

Gupta A. & Belnap N. 1993, The Revision Theory of Truth, MIT Press.

Orilia F. 2000, “Property Theory and the Revision Theory of Definitions,” J. Symbolic Logic 65: 212-246.

Orilia F. 2014, “Degrees of Validity and the Logical Paradoxes,” in E. Weber et al. (eds.), Logic, Reasoning and Rationality, Springer, pp. 179-196.

Peters D. 2014, “What Elements of Successful Scientific Theories Are the Correct Targets for ‘Selective’ Scientific Realism?,’ Phil. of Science 81: 377-397.

Priest G. 2006, In Contradiction, Oxford UP.