Online research in philosophy

Language acquisition is often said to be a process of mapping words into pre-existing concepts. Some researchers regard this theory as an immediate corollary of the assumption that all problem-solving involves the application of concepts. But in light of basic philosophical objections to the theory of language acquisition, that kind of rationale cannot be very persuasive. To have a reason to accept the theory of language acquisition despite the philosophical objections, we ought to have experimental evidence for the existence of concepts in prelinguistic children. One of the few lines of research that attempts to provide such evidence is the work of Paul Quinn, who claims that looking-time results show that four-month old infants form "category representations". This paper argues that Quinn's results have an alternative explanation. A distinction is drawn between conceptual thought and the perception of comparative similarity relations, and it is argued that Quinn's results can be explained in terms of the latter rather than the former.

Multidimensional space representations like those posited in Edelman's target article are not sufficient to capture all similarity phenomena. We discuss phenomena that are compatible with models of similarity that assume structured relational representations. An adequate model of similarity and perception will require multiple approaches to representation.

In a famous critique, Goodman dismissed similarity as a slippery and both philosophically and scientifically useless notion. We revisit his critique in the light of important recent work on similarity in psychology and cognitive science. Specifically, we use Tversky’s influential set-theoretic account of similarity as well as Gärdenfors’s more recent resuscitation of the geometrical account to show that, while Goodman’s critique contained valuable insights, it does not warrant a dismissal of similarity.

Criteria that aim to dichotomize cognition into rules and similarity are destined to fail because rules and similarity are not in genuine conflict. It is possible for a given cognitive domain to exploit rules without similarity, similarity without rules, or both (rules and similarity) at the same time.

In a famous critique, Goodman dismissed similarity as a slippery and both philosophically and scientifically useless notion. We revisit his critique in the light of important recent work on similarity in psychology and cognitive science. Specifically, we use Tversky’s influential set-theoretic account of similarity as well as Gärdenfors’s more recent resuscitation of the geometrical account to show that, while Goodman’s critique contained valuable insights, it does not warrant a dismissal of similarity.

The cognitive gain in the use of metaphor and simile is nicely elucidated by Tversky's theory of similarity. The features of the theory which are of special importance are the directionality and context-dependency of similarity judgments. These indicate the extent to which such judgments are classificatory and that similarity is not only the cause of an object's classification but is also a derivative of groupings. Metaphor and simile exploit certain cognitive features involved in the relation between classification, context and similarity judgments so as to make possible the creation of similarity, which, from a conceptual standpoint, is the prime motivation for metaphor.

We advance a theory of inductive reasoning based on similarity, and test it on arguments involving mammal categories. To measure similarity, we quantified the overlap of neural activation in left Brodmann area 37 (LBA37) in response to pictures of different categories; the choice of LBA37 is motivated by previous literature. The theory was tested against probability judgments for 160 arguments generated from 16 mammal categories and a common predicate. The theory’s predictions (based on neural similarity) correlate strongly with these estimates. Other brain regions previously implicated in semantic cognition yield similarities that also allow the model to predict inductive judgments accurately whereas use of rated similarity in place of neural similarity is less successful.

We advance a theory of inductive reasoning based on similarity, and test it on arguments involving mammal categories. To measure similarity, we quantified the overlap of neural activation in left Brodmann area 37 (lBA37) in response to pictures of different categories; the choice of lBA37 is motivated by previous literature. The theory was tested against estimated probability judgments for 160 arguments generated from 16 categories and a common predicate. The theory’s predictions (based on neural similarity) correlate strongly with these estimates. Other brain regions in the ventral visual pathway yield similarities that also allow the model to predict inductive judgments accurately whereas use of rated similarity in place of neural similarity is less successful. We conclude by extending the theory to aspects of causal reasoning and considering the relation between similarity and feature ratings of categories.

It is difficult to see how one can support the continuum between rules and similarity, as Pothos proposes. A similarity theory could dispense with the rules end of the continuum. The only thing that we need is one (or more than one) theory of similarity that goes beyond the stimulus-carrying information and behavioristic restrictions that have usually been attributed to similarity theories.

Bloom argues that concepts depend on psychological essentialism. He rejects the proposal that concepts are based on perceptual similarity spaces because it cannot account for how we handle new properties and does not fit with our intuitions about essences. I argue that by using a broader notion of similarity space, it is possible to explain these features of concepts.