Are Computational Transitions Sensitive to Semantics?

The formal conception of computation (FCC) holds that computational processes are not sensitive to semantic properties. FCC is popular, but it faces well-known difficulties. Accordingly, authors such as Block and Peacocke pursue a ‘semantically-laden’ alternative, according to which computation can be sensitive to semantics. I argue that computation is insensitive to semantics within a wide range of computational systems, including any system with ‘derived’ rather than ‘original’ intentionality. FCC yields the correct verdict for these systems. I conclude that there is only one promising strategy for semantically-laden theorists: identify special computational systems that help generate their own semantic properties, and then show that computation within those systems is semantically-laden. Unfortunately, the few existing discussions that pursue this strategy are problematic.     

SCIENCE AND SEMANTICS: THE CASE OF VAGUENESS AND SUPERVALUATION*

Abstract: It is widely assumed that the methods and results of science have no place among the data to which our semantics of vague predicates must answer. This despite the fact that it is well known that such prototypical vague predicates as ‘is bald’ play a central role in scientific research (e.g. the research that established Rogaine as a treatment for baldness). I argue here that the assumption is false and costly: in particular, I argue one cannot accept either supervaluationist semantics, or the criticism of that semantics offered by Fodor and Lepore, without having to abandon accepted, and unexceptionable, scientific methodology.     

Category mistakes and figurative language

Category mistakes are sentences such as ‘The number two is blue’ or ‘Green ideas sleep furiously’. Such sentences are highly infelicitous and thus a prominent view claims that they are meaningless. Category mistakes are also highly prevalent in figurative language. That is to say, it is very common for sentences which are used figuratively to be such that, if taken literally, they would constitute category mistakes. (Consider for example the metaphor ‘The poem is pregnant’, the metonymy ‘The White House decided to change its policy’, or a fictional use of ‘The tree was happy’.) In this paper I argue that the view that category mistakes are meaningless is inconsistent with many central and otherwise plausible theories of figurative language. Thus if the meaninglessness view is correct, the theories in question must each be rejected, and conversely, if any of the theories in question is correct, the meaninglessness view must be wrong. The debates concerning the semantics of figurative language and concerning the semantic status of category mistakes are closely connected.     

‘Ought’ and Control

Ethical theorists often assume that the verb ‘ought’ means roughly ‘has an obligation’; however, this assumption is belied by the diversity of ‘flavours’ of ought-sentences in English. A natural response is that ‘ought’ is ambiguous. However, this response is incompatible with the standard treatment of ‘ought’ by theoretical semanticists, who classify ‘ought’ as a member of the family of modal verbs, which are treated uniformly as operators. To many ethical theorists, however, this popular treatment in linguistics seems to elide an important distinction between agential and non-agential ought-statements. The thought is that ‘ought’ must have at least two senses, one implicating agency and connected to obligations, and another covering other uses. In this paper, I pursue some resolution of this tension between semantic theory and ethical theory with respect to the meaning of ‘ought’. To this end, I consider what I believe to be the most linguistically sophisticated argument for the view that the word ‘ought’ is ambiguous between agential and non-agential senses. This argument, due to Mark Schroeder, is instructive but based on a false claim about the syntax of agential ought-sentences—or so I attempt to show by first situating Schroeder's argument in its proper linguistic background and then discussing some syntactic evidence that he fails to appreciate. Then, I use the failure of this argument to motivate some more general reflections on how the standard treatment of ‘ought’ by theoretical semanticists might be refined in the light of the distinction important to ethical theory between agential and non-agential ought-statements, but also on how ethical theory might benefit from more careful study of the dominant treatment of modals as operators in theoretical semantics.     

Goal-oriented, flexible use of numerical operations by monkeys

Previous studies have shown that elementary aspects of numerical abilities have developed in non-human primates. In the present study, we explored the potential for the development of a novel ability in the use of numerical operations by macaque monkeys (Macaca fuscata): adequate selection of a series of numerical actions toward achieving a behavioral goal. We trained monkeys to use a pair of devices to selectively add or subtract items to/from a digital array in order to match a previously viewed sample array. The monkeys determined whether to add or subtract on the basis of the feedback about numerosity given to the monkeys, which was displayed as an outcome of each step of the numerical operation. We also found that monkeys adapted flexibly to changes in the numerical rule that determined the relationship between device use and numerical operation. Our model analysis found that the numerosity-based model was a better fit for the monkeys’ performance than was the reward-expectation-based model. Such a capacity for goal-oriented selection of numerical operations suggests a mechanism by which monkeys use numerical representations for purposeful behaviors.     

‘Knowledge’ as a natural kind term

Naturalists who conceive of knowledge as a natural kind are led to treat ‘knowledge’ as a natural kind term. ‘Knowledge,’ then, must behave semantically in the ways that seem to support a direct reference theory for other natural kind terms. A direct reference theory for ‘knowledge,’ however, appears to leave open too many possibilities about the identity of knowledge. Intuitively, states of belief count as knowledge only if they meet epistemic criteria, not merely if they bear a causal/historical relation to the term. I will develop this objection and show that it is grounded in modal considerations central to Kripke’s work on reference. I will also argue that a more plausible externalist semantics for natural kind terms disarms the objection.     

Semantics,experience and time

The computational hypothesis, with its inherent representationalism, and the dynamical hypothesis, with its apparent absence of representations and its commitment to continuous time, stand at an impasse. It is unclear how the dynamical stance can handle representational thought, or how computationalism can deal effectively with a tightly coupled, reciprocally causative agent–environment system in continuous transformation. Underlying this dilemma is the complex relation of mind to time, a relation encoded in the word experience. We must ask if any hypothesis describes a ‘device’ capable of experience? Yet what is an intelligence and its thought without experience? Is a computational device, whether supporting a symbolic processor or connectionist net, intrinsically condemned to a zero degree of experience? What is required of a dynamical device? It is argued here that ‘semantic’ intelligence and thought rests upon experience, fundamentally upon the invariance laws defined over time within conscious perception. The structure of experience is intrinsically unavailable to the computational device, limiting it to a ‘syntactic’ intelligence. An alternative conception of a device is offered, based on Bergson conjoined with Gibson, which supports the qualitative and structural aspects of experience and the semantic. It frames a dynamical model of perception and memory in which invariance laws are intrinsic, creates a deeper notion of situatedness, and supports a concept of semantically based, representative thought founded upon perception.     

Vision and abstraction: an empirical refutation of Nico Orlandi’s non-cognitivism

This article argues against the non-cognitivist theory of vision that has been formulated in the work of Nico Orlandi. It shows that, if we understand ‘representation’ in the way Orlandi recommends, then the visual system’s response to abstract regularities must involve the formation of representations. Recent experiments show that those representations must be used by the visual system in the production of visual experiences. Their effects cannot be explained by taking them to be non-visual effects involving attention or memory. This contradicts Orlandi’s version of the non-cognitivist hypothesis, but does so while vindicating her methodological position.     

‘Can’ and the Consequence Argument

The consequence argument is a powerful incompatibilist argument for the conclusion that, if determinism is true, what one does is what one must do. A major point of controversy between classical compatibilists and incompatibilists has been over the use of ‘can’ in the consequence argument. Classical compatibilists, holding that abilities to act are dispositions, have argued that ‘can’ should be analyzed as a conditional. But such an analysis of ‘can’ puts compatibilists in a position to grant the premises of the argument while denying the conclusion. Incompatibilists remain unconvinced, and this corner of the debate over free will has reached a dialectical impasse. The present paper has two aims. First, to offer a new dialectical point of entry into this dispute on behalf of incompatibilists. By making use of Angelika Kratzer's influential semantic work on ‘can’ and ‘must’, I argue that incompatibilists are in a position to offer a plausible, positive treatment of ‘can’ that favors their view. Second, even if one does not think incompatibilism is thereby true (for as we shall see there are places to push back), the Kratzer semantics yields a number of important insights concerning the consequence argument that should be of broad interest. ¹      

Sly Pete in Dynamic Semantics

In ‘Sly Pete’ or ‘standoff’ cases, reasonable speakers accept incompatible conditionals, and communicate them successfully to a trusting hearer. This paper uses the framework of dynamic semantics to offer a new model of the conversational dynamics at play in standoffs, and to articulate several puzzles posed by such cases. The paper resolves these puzzles by embracing a dynamic semantics for conditionals, according to which indicative conditionals require that their antecedents are possible in their local context, and update this body of information by eliminating the possibilities where the antecedent is true and the consequent is false. In this way, the dynamic analysis draws on insights from the material conditional and contextualist analyses, while explaining how standoffs are genuine disagreements.

     

Duck or rabbit? Reversing ambiguous figures and understanding ambiguous representations

In two studies we investigated 3‐ to 5‐year‐old children’s ability to reverse ambiguous figures and the relation between this ability and the ability to understand multiple representations. Children never reversed before they were informed of the two alternative interpretations of the figures. Even when they were informed of the alternatives and understood that both were possible, 3‐year‐olds and most 4‐year‐olds did not reverse. In contrast, a majority of 5‐year‐olds did reverse. In general, children only reversed if they also passed a standard false belief task. However, there was a closer correlation between reversals and a ‘droodle’ task that involved an understanding of the ambiguity of perceptual representations. These results suggest that the immediate experience of reversal may depend on a more abstract understanding of ambiguous representations.     

Representations gone mental

Many philosophers and psychologists have attempted to elucidate the nature of mental representation by appealing to notions like isomorphism or abstract structural resemblance. The ‘structural representations’ that these theorists champion are said to count as representations by virtue of functioning as internal models of distal systems. In his 2007 book, Representation Reconsidered, William Ramsey endorses the structural conception of mental representation, but uses it to develop a novel argument against representationalism, the widespread view that cognition essentially involves the manipulation of mental representations. Ramsey argues that although theories within the ‘classical’ tradition of cognitive science once posited structural representations, these theories are being superseded by newer theories, within the tradition of connectionism and cognitive neuroscience, which rarely if ever appeal to structural representations. Instead, these theories seem to be explaining cognition by invoking so-called ‘receptor representations’, which, Ramsey claims, aren’t genuine representations at all—despite being called representations, these mechanisms function more as triggers or causal relays than as genuine stand-ins for distal systems. I argue that when the notions of structural and receptor representation are properly explicated, there turns out to be no distinction between them. There only appears to be a distinction between receptor and structural representations because the latter are tacitly conflated with the ‘mental models’ ostensibly involved in offline cognitive processes such as episodic memory and mental imagery. While structural representations might count as genuine representations, they aren’t distinctively mental representations, for they can be found in all sorts of non-intentional systems such as plants. Thus to explain the kinds of offline cognitive capacities that have motivated talk of mental models, we must develop richer conceptions of mental representation than those provided by the notions of structural and receptor representation.     

Free Thinking for Expressivists

Abstract

This paper elaborates and defends an expressivist account of the claims of mind-independence embedded in ordinary moral thought. In response to objections from Zangwill and Jenkins it is argued that the expressivist ‘internal reading’ of such claims is compatible with their conceptual status and that the only ‘external reading’ available doesn't commit expressivisists to any sort of subjectivism. In the process a ‘commitment-theoretic’ account of the semantics of conditionals and negations is defended.     

A quantum approach to visual consciousness

A theoretical approach relying on quantum computation in microtubules within neurons can potentially resolve the enigmatic features of visual consciousness, but raises other questions. For example, how can delicate quantum states, which in the technological realm demand extreme cold and isolation to avoid environmental ‘decoherence’, manage to survive in the warm, wet brain? And if such states could survive within neuronal cell interiors, how could quantum states grow to encompass the whole brain? We present a physiological model for visual consciousness that can accommodate brain-wide quantum computation according to the Penrose–Hameroff ‘Orch OR’ model. In this view, visual consciousness occurs as a series of several-hundred-millisecond epochs, each comprising ‘crescendo sequences’ of quantum computations occurring at ∼40 Hz.     

Existential Import in Cartesian Semantics

The paper explores the existential import of universal affirmative in Descartes, Arnauld and Malebranche. Descartes holds, inconsistently, that eternal truths are true even if the subject term is empty but that a proposition with a false idea as subject is false. Malebranche extends Descartes’ truth-conditions for eternal truths, which lack existential import, to all knowledge, allowing only for non-propositional knowledge of contingent existence. Malebranche's rather implausible Neoplatonic semantics is detailed as consisting of three key semantic relations: illumination by which God's ideas cause mental terms, creation by which God's ideas cause material substances by a kind of ‘ontic privation’, and sensation in which brain events occasion states of mental awareness. In contrast, Arnauld distinguishes two types of propositions – necessary and contingent – with distinct truth-conditions, one with and one without existential import. Arnauld's more modern semantics is laid out as a theory of reference that substitutes earlier causal accounts with one that adapts the medieval notion of objective being. His version anticipates modern notions of intentional content and appeals in its ontology only to substances and their modes.     

The Causal Relevance of Content to Computation

Many philosophers worry that the classical computational theory of mind (CTM) engenders epiphenomenalism. Building on Block’s (1990) discussion, I formulate a particularly troubling version of this worry. I then present a novel solution to CTM’s epiphenomenalist conundrum. I develop my solution within an interventionist theory of causal relevance. My solution departs substantially from orthodox versions of CTM. In particular, I reject the widespread picture of digital computation as formal syntactic manipulation. 1     

Future Contingents,Indeterminacy and Context

In Facing the Future, Belnap et al. reject bivalence and propose double time reference semantics to give a pragmatic response to the following assertion problem: how can we make sense of assertions about future events made at a time when the outcomes of those events are not yet determined? John MacFarlane employs the same semantics, now bolstered with a relative‐truth predicate, to accommodate the following apparently conflicting intuitions regarding the truth‐value of an uttered future contingent: at the moment of utterance, if asked to evaluate the truth‐value of the asserted future contingent one has the intuition that the assertion is neither true nor false, yet later, at the moment of the predicted event, one has the intuition that the assertion was, already, either true or false. Both MacFarlane and Belnap assume that assertions of future contingents have complete propositional content – the traditional propositional contents that, according to him ‘are the contents of assertions and beliefs’. This assumption is challenged.     

Husserl on Meaning,Grammar, and the Structure of Content

Husserl’s Logical Grammar is intended to explain how complex expressions can be constructed out of simple ones so that their meaning turns out to be determined by the meanings of their constituent parts and the way they are put together. Meanings are thus understood as structured contents and classified into formal categories to the effect that the logical properties of expressions reflect their grammatical properties. As long as linguistic meaning reduces to the intentional content of pre-linguistic representations, however, it is not trivial to account for how semantics relates to syntax in this context. In this paper, I analyze Husserl’s Logical Grammar as a system of recursive rules operating on representations and suggest that the syntactic form of representations (both mental and linguistic) contributes to their semantics because it carries information about semantic role. I further discuss Husserl’s syntactic account of the unity of propositions and argue that, on this  account, logical form supervenes on syntactic form. In the last section I draw some implications for the phenomenology of thought and conjecture that the structural features it displays are likely to convey the syntactic structures of an underlying language-like representational system.