Fitch's knowability axioms are incompatible with quantum theory

How can we consistently model the knowledge of the natural world provided by physical theories? Philosophers frequently use epistemic logic to model reasoning and knowledge abstractly, and to formally study the ramifications of epistemic assumptions. One famous example is Fitch's paradox, which begins with minimal knowledge axioms and derives the counter-intuitive result that "every agent knows every true statement." Accounting for knowledge that arises from physical theories complicates matters further. For example, quantum mechanics allows observers to model other agents as quantum systems themselves, and to make predictions about measurements performed on each others' memories. Moreover, complex thought experiments in which agents' memories are modelled as quantum systems show that multi-agent reasoning chains can yield paradoxical results. Here, we bridge the gap between quantum paradoxes and foundational problems in epistemic logic, by relating the assumptions behind the recent Frauchiger-Renner quantum thought experiment and the axioms for knowledge used in Fitch's knowability paradox. Our results indicate that agents' knowledge of quantum systems must violate at least one of the following assumptions: it cannot be distributive over conjunction, have a kind of internal continuity, and yield a constructive interpretation all at once. Indeed, knowledge provided by quantum mechanics apparently contradicts traditional notions of how knowledge behaves; for instance, it may not be possible to universally assign objective truth values to claims about agent knowledge. We discuss the relations of this work to results in quantum contextuality and explore possible modifications to standard epistemic logic that could make it consistent with quantum theory.Comment: 22 + 7 page

How Genealogies Can Affect the Space of Reasons

Can genealogical explanations affect the space of reasons? Those who think so commonly face two objections. The first objection maintains that attempts to derive reasons from claims about the genesis of something commit the genetic fallacy—they conflate genesis and justification. One way for genealogies to side-step this objection is to focus on the functional origins of practices—to show that, given certain facts about us and our environment, certain conceptual practices are rational because apt responses. But this invites a second objection, which maintains that attempts to derive current from original function suffer from continuity failure—the conditions in response to which something originated no longer obtain. This paper shows how normatively ambitious genealogies can steer clear of both problems. It first maps out various ways in which genealogies can involve non-fallacious genetic arguments before arguing that some genealogies do not invite the charge of the genetic fallacy if they are interpreted as revealing the original functions of conceptual practices. However, they then incur the burden of showing that the conditions relative to which practices function continuously obtain. Taking its cue from the genealogies of E. J. Craig, Bernard Williams, and Miranda Fricker, the paper shows how model-based genealogies can avoid continuity failures by identifying bases of continuity in the demands we face

Combining logic and probability in tracking and scene interpretation

The paper gives a high-level overview of some ways in which logical representations and reasoning can be used in computer vision applications, such as tracking and scene interpretation. The combination of logical and statistical approaches is also considered

Radically enactive high cognition

I advance the Radically Enactive Cognition (REC) program by developing Hutto & Satne’s (2015) and Hutto & Myin’s (2017) idea that contentful cognition emerges through sociocultural activities, which require a contentless form of intentionality. Proponents of REC then face a functional challenge: what is the function of higher cognitive skills, given the empirical findings that engaging in higher-cognitive activities is not correlated with cognitive amelioration (Kornblith, 2012)? I answer that functional challenge by arguing that higher cognition is an adaptive tool of the social systems we are embedded in, therefore, it is not necessarily aimed at achieving better cognitive states. In order to do so, I suggest interpreting key insights from autopoietic enactivism through REC lenses

Enhanced tracking and recognition of moving objects by reasoning about spatio-temporal continuity.

A framework for the logical and statistical analysis and annotation of dynamic scenes containing occlusion and other uncertainties is presented. This framework consists of three elements; an object tracker module, an object recognition/classification module and a logical consistency, ambiguity and error reasoning engine. The principle behind the object tracker and object recognition modules is to reduce error by increasing ambiguity (by merging objects in close proximity and presenting multiple hypotheses). The reasoning engine deals with error, ambiguity and occlusion in a unified framework to produce a hypothesis that satisfies fundamental constraints on the spatio-temporal continuity of objects. Our algorithm finds a globally consistent model of an extended video sequence that is maximally supported by a voting function based on the output of a statistical classifier. The system results in an annotation that is significantly more accurate than what would be obtained by frame-by-frame evaluation of the classifier output. The framework has been implemented and applied successfully to the analysis of team sports with a single camera. Key words: Visua