This chapter summarizes how the human auditory system translates the acoustic speech sound from acoustic energy into a neural signal. Initial processing begins with the outer ear, followed by mechanical amplification in the middle ear (via the ossicles). The inner ear contains the cochlea, which is what converts physical energy to a neural signal that is transmitted to the auditory nerve. The subcortical auditory pathway includes the cochlear nucleus, inferior colliculus, and medial geniculate body. Subcortical auditory processing can be assessed with EEG to measure the auditory brainstem response (ABR) or frequency following response (FFR). The cortical area receiving auditory information, auditory cortex, contains a number of distinct subfields. The chapter also reviews common approaches for clinical evaluation of hearing sensitivity, notably the pure-tone audiogram, and common challenges to hearing (including sensory-neural hearing loss, noise induced hearing loss), and the function of cochlear implants.

This chapter introduces the idea of language as a means to communicate ideas to other people. The speech chain – following the path of language from the mind of the speaker through to an acoustic signal, eventually interpreted by the mind of the listener – is introduced as an organizational framework. Of special note, all of the stages between talker and listener can influence the effectiveness of communication. The chapter provides a summary of central challenges associated with spoken language, including categorical perception, time-constrained understanding, flexibility, and multimodal integration. It then introduces several “big picture” themes from the book: stability versus flexibility, the importance of context, bottom-up versus top-down processing, hierarchical organization, the role of task demands, and neuroanatomical considerations related to localization and lateralization.

This chapter provides an overview of how listeners’ brains process building blocks of speech: phonemes (that is, speech sounds) and word forms. Phonemes are processed bilaterally in posterior portions of the superior temporal sulcus. Compared to isolated phonemes, spoken words are acoustically more complex and associated with both grammatical status and meaning. Spoken word processing relies on bilateral temporal cortex, including portions of the superior temporal gyrus and middle temporal gyrus. The role of acoustic context on word recognition is also covered, including effects of speech rate and how listeners interpret speech sounds in relation to what surrounds them. Theoretical perspectives covered in the chapter include predictive coding (in which unpredicted sounds are associated with increased activity) and lexical competition (in which words with similar-sounding competitors are more difficult to understand). The hemispheric lateralization of these processes is also discussed, including the important historical development of the Wada test.

This chapter delves a little more deeply into a particular experimental investigation from the seventeenth century. Robert Boyle’s air-pump allowed him to evacuate (nearly) all of the air from an enclosed chamber. He sought to investigate various phenomena, including the recent discovery that, in a tube filled with mercury and open at one end and then inverted into an open dish filled with mercury, an apparently empty space will appear at the top (closed) end of the tube. Boyle’s experiments are credited with having led to the modern conception of air pressure, but his conclusions were met with controversy.

The falsificationist proposes a model of scientific reasoning in which deductive logic alone is used. This chapter examines a logical gap in scientific reasoning that applies even to deductive arguments used in falsifying general hypotheses. Drawing experimental predictions from general hypotheses requires additional assumptions, and the logic of falsifying arguments does not determine whether it is the hypothesis under test or these additional (auxiliary) assumptions that should be considered false. This chapter considers the treatment of this “problem of underdetermination” by Pierre Duhem, and how it can be applied to an experiment performed by Léon Foucault to test a theory about the physical nature of light. The chapter also compares Duhem’s discussion of the problem of underdetermination with W. V. O. Quine’s much-discussed underdetermination thesis. Appeals to underdetermination play important roles in many ongoing debates, making this chapter important for much of the material to come.

After an introduction to the general notion of relativism in philosophy, the chapter considers an approach to the study of scientific inquiry that is explicit in its commitment to relativism: the strong program in the sociology of knowledge. According to the strong program, which purports to give a social scientific account of science, scientific knowledge is not so much discovered as constructed by social dynamics that produce scientific consensus. The limits of such an account are explored by discussing both sociological and anthropological approaches. The social constructionist account has been applied to Robert Boyle’s experiments with an air-pump and the criticisms directed against them. Applying similar ideas to physicists’ attempts to detect gravity waves has led to the formulation of a problem known as the experimenters’ regress. Through such cases, the chapter sees how defenders of social constructionist accounts draw upon both history and social scientific investigations of current science. The chapter then surveys philosophical and historical criticisms of this approach.

In the first of two chapters on probability in scientific inquiry, the basic ideas of probability theory are introduced through examples involving games of chance. The chapter then focuses on the Bayesian approach to probability, which adopts the stance that probabilities should be understood as expressions about the degrees of belief. The Bayesian approach as a general framework for probability is explained through examples involving betting that extend beyond games of chance, which also allows the introduction of the idea of probabilistic coherence as a condition of rational partial belief. We are then finally ready for Bayes’s theorem, a theorem of the probability calculus that plays a central role in the Bayesian account of learning from evidence. That account is illustrated with a historically motivated example from the history of paleontology. The chapter considers objections to the Bayesian approach and the resources Bayesians may draw on for answering those objections.

Scientific realists defend the proposition that successful scientific theories in the mature sciences should be regarded as at least approximately true because that provides the best explanation of the fact that scientists use such theories successfully. Two important types of arguments against scientific realism are then considered. The historical argument appeals to the fact that seemingly successful theories have in the past turned out to be not even approximately true. The empiricist argument holds that because scientific realists believe claims about things that can never be observed, they violate the scientific commitment to subject claims to empirical assessment. Responses on behalf of scientific realism are considered. The chapter concludes by surveying engagements with realism in science that depart from the dialectic just sketched. These include considerations based on experimentation and experimental practice, varieties of structural realism, and perspectival realism.

This chapter examines how the history of science became a resource for the development and defense of important alternatives to logical empiricist views of scientific theory and the growth of scientific knowledge. The chapter also examines the different meanings attached to scientific paradigms in Thomas Kuhn’s account of scientific change and different notions of incommensurability implicated in his account. Like other postpositivist thinkers, Kuhn rejects the logical empiricist idea of separating observational and theoretical language, arguing instead that observation is theory-laden. The history of science plays an important but distinct role in Imre Lakatos’s methodology of scientific research programs, which aims to represent the rationality of scientific thought. The chapter concludes by examining Paul Feyerabend’s epistemological anarchism, which appears to cast doubt on the prospects for providing a systematic account of scientific rationality. Are Feyerabend’s views as extreme as their expression suggests, or is there another way to understand his provocations?