The Place of Reasons in Epistemology

2018 ◽  
Author(s):  
Kurt Sylvan ◽  
Ernest Sosa
Keyword(s):  
Building Block ◽  
Epistemic Normativity ◽  
Epistemic Reasons ◽  
Middle Ground ◽  
Theoretic Property ◽  
Propositional Justification ◽  
Doxastic Justification ◽  
The Road ◽  
Necessary And Sufficient

This chapter defends a middle ground between two extremes in the literature on the place of reasons in epistemology. Against members of the “reasons first” movement, we argue that reasons are not the sole grounds of epistemic normativity. We suggest that the virtue-theoretic property of competence is rather the key building block. To support this approach, we note that reasons must be possessed to ground central epistemic properties, and argue that possession is grounded in competence. But while we here diverge with reasons-firsters, we also distance ourselves from those who deem reasons unimportant. Indeed, we hold that having sufficient epistemic reasons is necessary and sufficient for propositional justification, and that proper basing on them yields doxastic justification. But since possession and proper basing are grounded in competence, reasons are not the end of the road: competence enables them to do their work, putting them—and us—in the middle.

Why Only Evidential Considerations Can Justify Belief

2018 ◽  
Author(s):  
Kate Nolfi
Keyword(s):  
Alternative Explanation ◽  
Justify Belief ◽  
Epistemic Normativity ◽  
Epistemic Reasons ◽  
Aim Of Belief ◽  
The Way

At least when we restrict our attention to the epistemic domain, it seems clear that only considerations which bear on whether p can render a subject’s belief that p epistemically justified, by constituting the reasons on the basis of which she believes that p. And we ought to expect any account of epistemic normativity to explain why this is so. Extant accounts generally appeal to the idea that belief aims at truth, in an effort to explain why there is a kind of evidential constraint on the sorts of considerations that can be epistemic reasons. However, there are grounds for doubting that belief, in fact, aims at truth in the way that these accounts propose. This chapter develops an alternative explanation of why it is that non-evidential considerations cannot be epistemic reasons by taking seriously the idea that the constitutive aim of belief is fundamentally action-oriented.

Propositional and doxastic justification

2021 ◽  
pp. 107-137
Author(s):  
Sven Rosenkranz
Keyword(s):  
Epistemic Situation ◽  
Propositional Justification ◽  
Doxastic Justification

Drawing on the results of previous chapters, the proposal is made to interpret the complex operator ⌜¬K¬K⌝ as encoding propositional justification and the complex operator ⌜¬K¬K⌝ as encoding doxastic justification—where in each case justification is understood to be justification all things considered. Accordingly, not only propositional but also doxastic justification is construed as a feature of one’s epistemic situation rather than a feature of one’s beliefs. On this view, both types of justification are non-factive. The proposed account is defended against a number of putative counterexamples, the allegation that it confuses epistemic permissibility with epistemic blamelessness, and the charge that it fails to heed plausible reliabilist constraints on justification. At crucial junctures this defence relies on the availability of theorems governing the aforementioned complex operators that were proved in chapter 5.

scholarly journals Structure of the RZZ complex and molecular basis of Spindly-driven corona assembly at human kinetochores

2021 ◽  
Author(s):  
Tobias Raisch ◽  
Giuseppe Ciossani ◽  
Ennio d’Amico ◽  
Verena Cmentowski ◽  
Sara Carmignani ◽  
...  
Keyword(s):  
High Resolution ◽  
Binding Site ◽  
Molecular Mechanism ◽  
Building Block ◽  
Molecular Basis ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Structural Requirements ◽  
Necessary And Sufficient

In metazoans, a ≍1 megadalton (MDa) super-complex comprising the Dynein-Dynactin adaptor Spindly and the ROD-Zwilch-ZW10 (RZZ) complex is the building block of a fibrous biopolymer, the kinetochore fibrous corona. The corona assembles on mitotic kinetochores to promote microtubule capture and spindle assembly checkpoint (SAC) signaling. We report here a high-resolution cryo-EM structure that captures the essential features of the RZZ complex, including a farnesyl binding site required for Spindly binding. Using a highly predictive in vitro assay, we demonstrate that the SAC kinase MPS1 is necessary and sufficient for corona assembly at supercritical concentrations of the RZZ-Spindly (RZZS) complex, and describe the molecular mechanism of phosphorylation-dependent filament nucleation. We identify several structural requirements for RZZS polymerization in rings and sheets. Finally, we identify determinants of kinetochore localization and corona assembly of Spindly. Our results describe a framework for the long-sought-for molecular basis of corona assembly on metazoan kinetochores.

Competing views

2021 ◽  
pp. 170-188
Author(s):  
Sven Rosenkranz
Keyword(s):  
Epistemic Possibility ◽  
Metaphysical Possibility ◽  
Propositional Justification ◽  
Present Account ◽  
Doxastic Justification ◽  
The Third ◽  
Justified Belief ◽  
Rule Out

The present account, which construes justification as a kind of epistemic possibility of knowing, or of being in a position to know, competes with three recently advanced theories of justification. Of these competitors, the first two construe doxastic justification as the metaphysical possibility of knowing. While they differ in some details, these views share certain problematic features: they fail to yield a corresponding account of propositional justification, have trouble vindicating an intuitive principle of closure for justified belief, and fail to comply with the independently plausible principle that if one has a justified belief, one is in no position to rule out that one has knowledge. The present account does not have these problematic features. According to the third competitor, |φ‎| is propositionally justified in one’s situation just in case it would be abnormal—and so require explanation—if |φ‎| were to be false in the presence of the evidence that one possesses in that situation. This normic theory of justification validates the principle that propositional justification agglomerates over conjunction, and in so doing, violates the constraint that propositions of the form ⌜φ‎ & ¬Kφ‎⌝ never be justified. It likewise contradicts the independently plausible principle that whenever |φ‎| is propositionally justified all things considered, |¬Kφ‎| is not. The present account does not face these problems, since it rejects the relevant agglomeration principle and treats the condition encoded by ⌜¬K¬Kφ‎⌝ as luminous.

scholarly journals Realization of an Ergodic Markov Chain as a Random Walk Subject to a Synchronizing Road Coloring

2011 ◽  
Vol 48 (3) ◽  
pp. 766-777 ◽  
Author(s):  
Kouji Yano ◽  
Kenji Yasutomi
Keyword(s):  
Markov Chain ◽  
Random Walk ◽  
Ergodic Markov Chain ◽  
The Road ◽  
The Past ◽  
Coupling From The Past ◽  
Random Mappings ◽  
On The Road ◽  
Necessary And Sufficient ◽  
Coloring Theorem

An ergodic Markov chain is proved to be the realization of a random walk in a directed graph subject to a synchronizing road coloring. The result ensures the existence of appropriate random mappings in Propp-Wilson's coupling from the past. The proof is based on the road coloring theorem. A necessary and sufficient condition for approximate preservation of entropies is also given.

scholarly journals On the Relationship between Propositional and Doxastic Justification

2020 ◽  
Author(s):  
John Turri
Keyword(s):  
Epistemic Justification ◽  
Significant Advance ◽  
Propositional Justification ◽  
Doxastic Justification ◽  
The Relationship ◽  
In Virtue Of ◽  
Orthodox View

I argue against the orthodox view of the relationship between propositional and doxastic justification. The view under criticism is: if p is propositionally justified for S in virtue of S’s having reason(s) R, and S believes p on the basis of R, then S’s belief that p is doxastically justified. I then propose and evaluate alternative accounts of the relationship between propositional and doxastic justification, and conclude that we should explain propositional justification in terms of doxastic justification. If correct, this proposal would constitute a significant advance in our understanding of the sources of epistemic justification.

Concluding Remarks

2021 ◽  
pp. 264-268
Author(s):  
Sven Rosenkranz
Keyword(s):  
Epistemic Justification ◽  
Propositional Justification ◽  
Doxastic Justification ◽  
Negative Introspection

According to the account of epistemic justification developed in this book, one has propositional justification for p just in case one is in no position to know that one is in no position to know p; and one has doxastic justification for p just in case one is in no position to know that one does not know p. The account gives internalists much of what they want from a theory of justification—in particular, a notion of justification according to which propositional justification is non-factive and luminous, underwrites principles of positive and negative introspection, and remains available to the victims of systematic deception. All the while, that notion is explained in terms of other notions that clearly belong to the knowledge-firsters’ toolkit, and coheres with an externalist account of the grounds for justification.

Grounds for justification

2021 ◽  
pp. 189-228
Author(s):  
Sven Rosenkranz
Keyword(s):  
Propositional Justification ◽  
Doxastic Justification ◽  
Comprehensive Account ◽  
Evidential Probability ◽  
Radical Scepticism

We must distinguish between the condition of a proposition’s being justified in one’s situation and the metaphysical grounds determining that this condition obtains. While the former is luminous, the latter need not be. It is argued that knowing is a strict full ground for doxastic justification, and being in a position to know is a strict full ground for propositional justification. It follows that facts about one’s evidence that serve as strict partial grounds for knowing are strict partial grounds for doxastic justification, and facts about one’s evidence that serve as strict partial grounds for being in a position to know are strict partial grounds for propositional justification. Even if only partial, such evidential grounds can only be assumed to be available in some, but not all, cases in which one has doxastic justification without knowing, and propositional justification without being in a position to know. A more comprehensive account identifies facts about evidential probabilities as facts that yield strict full grounds for justification. While one’s evidence is the totality of what one is in a position to know, the evidential probability of p equals the probability of p conditional on one’s evidence. The account requires taking the notion of evidential probability as primitive. It uniformly applies to all cases of justification, including the bad cases envisaged by radical scepticism. Degrees of strength of justification are explained in terms of facts about evidential probabilities. Just as their grounds, degrees of strength of justification are not luminous, even if justification is.

Rigid and Flat Foldability of a Degree-Four Vertex in Origami

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Luca Zimmermann ◽  
Tino Stanković
Keyword(s):  
Building Block ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Deployable Structures ◽  
Design Synthesis ◽  
Spherical Mechanisms ◽  
Necessary And Sufficient

Abstract Rigid foldability is the property of an origami that folds continuously from an unfolded to a folded state without deformation in its facets. Although extensively researched, there exist no intrinsic conditions for the rigid foldability of a degree-four vertex, which is the simplest possible origami building block that folds nontrivially. In this paper, we derive a necessary and sufficient condition for the rigid foldability of a degree-four vertex and show that it can be reduced to a purely sufficient condition, which is equivalent to a known condition from the realm of spherical mechanisms. The implications of these conditions are discussed, which reveals the connection between rigid and flat foldability, the two most important mathematical notions in origami. In practice, this work further contributes to the design synthesis and analysis of deployable structures, in which the mechanics of degree-four vertices is omnipresent.

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