This chapter gives overviews of two scientifically objective approaches to sounds: acoustics and the physiology of audition. It provides encapsulations of key notions such as the propagation, refraction, and reverberation of sound waves, frequency and pressure amplitude, the structure of the human ear, and the neural and electrochemical bases of hearing. It then examines how these objective sciences of hearing cannot remove significant subjective components from listening and, in fact, point us in the direction of a constructivist understanding of sonic experience. For example, it considers how we construct perception of fundamental frequencies that do not exist physically out of harmonics, how simply thinking that we see sound sources changes how we hear, and other cases of “acoustic illusions.” It also shows how the human privileging of language means that some sounds stand out from others, such as a conversation in a noisy room (the “cocktail party effect”), and how language more generally shapes sonic perception.