Markus Werning

We defend a realistic attitude towards biological species. We argue that two species are not different species because they differ in intrinsic features, be they phenotypic or genomic, but because they are separated with regard to gene flow. There are no intrinsic species essences. However, there are relational ones. We argue that bearing a gene flow relation to conspecifics may serve as the essence of a species. Our view of the species as a Gene-Flow Community differs from Mayr’s definition of the species as a reproductive community. In a reproductive community, each organism is able to successfully reproduce with each other. However, there are species in which geographically distant organisms lost their ability to successfully reproduce, due to strong genetic adaptations to the respective local environmental conditions. Despite this loss of the ability to mutually reproduce, they are still bound by gene flow via continuous intermediate populations. This replacement of Mayr’s notion of an interbreeding potential as a criterion for species membership has important implications for the treatment of populations in allopatry and sympatry.

This article proposes a neurobiologically motivated theory of meaning as internal representation that holds on to the principle of compositionality, but negates the principle of semantic constituency. The approach builds on neurobiological findings regarding topologically structured cortical feature maps and the mechanism of object-related binding by neuronal synchronization. It incorporates the Gestalt principles of psychology and is implemented by recurrent neural networks. The semantics to be developed is structurally analogous to some variant of model-theoretical semantics. The semantics to be developed is a neuro-emulative model-theoretical semantics of a first-order language. The model-theoretical semantics is merely denotational and does not imply anything about the structures of the mind or the underlying neural mechanisms that enable producing and comprehend meaningful expressions. The relation between a mental representation and its content is some form of causal-informational covariation.

Colloquially, episodic memory is described as “the memory of personally experienced events”. Even though episodic memory has been studied in psychology and neuroscience for about six decades, there is still great uncertainty as to what episodic memory is. Here we ask how episodic memory should be characterized in order to be validated as a natural kind. We propose to conceive of episodic memory as a knowledge-like state that is identified with an experientially based mnemonic representation of an episode that allows for a mnemonic simulation thereof. We call our analysis the Sequence Analysis of Episodic Memory since episodes will be analyzed in terms of sequences of events. Our philosophical analysis of episodic memory is driven and supported by experimental results from psychology and neuroscience. We discuss selected experimental results that provide exemplary evidence for uniform causal mechanisms underlying the properties of episodic memory and argue that episodic memory is a natural kind. The argumentation proceeds along three cornerstones: First, psychological evidence suggests that a violation of any of the proposed conditions for episodic memory amounts to a deficiency of episodic memory and no form of memory or cognitive process but episodic memory fulfills them. Second, empirical results support a claim that the principal anatomical substrate of episodic memory is the hippocampus. Finally, we can pin down causal mechanisms onto neural activities in the hippocampus to explain the psychological states and processes constituting episodic memory

What has the self to be like such that introspective awareness of it is possible? The paper asks if Descartes’s idea of an inner self can be upheld and discusses this issue by invoking two principles: the phenomenal transparency of experience and the semantic compositionality of conceptual content. It is assumed that self-awareness is a second-order state either in the domain of experience or in the domain of thought. In the former case self-awareness turns out empty if experience is transparent. In the latter, it can best be conceived of as a form of mental quotation. Various proposed analyses of direct and indirect quotation are discussed and tested regarding their applicability to thought. It is concluded that, on the assumption of compositionality, the inner self is only insofar accessible to awareness as it has an accessible phonological structure, as apparently only inner speech does

The paper argues that cognitive states of biological systems are inherently temporal. Three adequacy conditions for neuronal models of representation are vindicated: the compositionality of meaning, the compositionality of content, and the co-variation with content. Classicist and connectionist approaches are discussed and rejected. Based on recent neurobiological data, oscillatory networks are introduced as a third alternative. A mathematical description in a Hilbert space framework is developed. The states of this structure can be regarded as conceptual representations satisfying the three conditions

The doctrine that meanings are entitieswith a determinate and independent reality is often believed tohave been undermined by Quine's thought experiment of radicaltranslation, which results in an argument for the indeterminacy oftranslation. This paper argues to the contrary. Starting fromQuine's assumption that the meanings of observation sentences arestimulus meanings, i.e., set-theoretical constructions of neuronalstates uniquely determined by inter-subjectively observable facts,the paper shows that this meaning assignment, up to isomorphism,is uniquely extendable to all expressions that occur inobservation sentences. To do so, a theorem recently proven byHodges is used. To derive the conclusion, one only has to assumethat languages are compositional, abide by a generalized contextprinciple and by what I call the category principle. Theseassumptions originating in Frege and Husserl are coherent withQuine's overall position. It is concluded that Quine'snaturalistic approach does not justify scepticism with regard tomeaning, but should rather result in a view that affiliatessemantics with neuroscience.