From lecture transcript to teaching system

Perception begins as physics: structured energy and matter in the environment interact with biological receptors, are transduced into neural signals, and are ultimately interpreted as conscious percepts. This article develops lecture notes on the physics of perception for an upper-level Sensation and Perception course. The central aim is to specify what, exactly, sensory systems detect---not in terms of subjective experience alone, but in terms of measurable physical variables that reach the body and can be transformed into neural codes. We articulate a three-stage analysis that helps resolve classic philosophical puzzles (e.g., the ``tree falling in a forest'') by separating (i) events in the physical world, (ii) the subset of those events that can in principle be detected by a given organism, and (iii) the organism's perceptual experience and report. We then survey core forms of environmental energy relevant to human sensation: electromagnetic radiation (vision), mechanical pressure waves (audition), mechanical and thermal interactions at body surfaces and within tissues (somatosensation, proprioception, vestibular function), and chemical structures dissolved in liquids or suspended in air (gustation and olfaction). Throughout, we emphasize that receptor systems are adaptive sampling devices: they restrict access to only a narrow band of the physical world and introduce lawful distortions (amplification, attenuation, compression, nonlinearities) that support behavioral goals rather than veridical recording. We integrate foundational psychophysics (absolute thresholds, just noticeable differences, psychometric functions, Weber fractions) and decision-theoretic signal detection theory (detection as inference under uncertainty) as methodological bridges between physics and experience. Finally, we discuss the epistemic implications of sensory envelopes for evaluating extraordinary perceptual claims and for understanding why perception is reliable enough for survival yet systematically limited and biased.

Psychology’s modern history can be read as a sequence of changing answers to a deceptively simple question: What, exactly, is psychology allowed to study? From the late nineteenth century onward, the field repeatedly redrew its boundaries in response to conceptual disputes and methodological constraints. This lecture-based article offers an integrative narrative of major historical inflection points: Wundt’s laboratory psychology and the attempt to render consciousness measurable; early introspectionist programs and their internal tensions; Freud’s proposal of unconscious motivation and conflict; Jung’s expansion toward symbolic, cultural, and potentially transpersonal layers of mind; behaviorism’s rejection of mentalistic explanation in favor of observable stimulus--response relations and operant learning; Piaget’s developmental constructivism and the claim that children’s “wrong” answers reveal coherent cognitive structures; Eysenck’s psychometric and experimental critique of psychoanalysis and his insistence on measurement, prediction, and falsifiability in personality science; and Festinger’s cognitive dissonance theory as a paradigm for studying belief revision under social and motivational pressures. Throughout, the guiding theme is not date memorization but the evolution of permissible questions, accepted evidence, and dominant paradigms. The article concludes by situating contemporary cognitive neuroscience as a powerful, though historically contingent, synthesis that still grapples with enduring challenges: the privacy of subjective experience, the interpretation of correlational evidence, and the philosophical implications of explaining agency through mechanisms.

The term \emph{disorder} is ubiquitous in clinical psychology, psychiatry, and neuropsychology, yet its conceptual basis is frequently assumed rather than argued. This paper develops lecture-style notes for PSYC 3910 (Brain Dysfunction and Recovery) that place the question ``What is a disorder?'' prior to specific neuropsychological syndromes. Using classic debates in the philosophy of psychiatry and instructive neurological case phenomena (e.g., anosognosia, somatoparaphrenia, amnesia, delusional misidentification, phantom limbs), the notes distinguish description from explanation, observation from inference, and mechanistic account from moral judgment. The central aim is methodological: to cultivate disciplined skepticism toward both uncritical medicalization (the fallacy that naming a pattern explains it) and skeptical dualism (the fallacy that value-laden boundaries imply a lack of biological basis). The paper proposes a practical framework for evaluating disorder claims: (i) specify the target phenomenon, (ii) clarify the normative standard invoked, (iii) separate impairment, distress, and social deviance, (iv) identify the evidential bridge from brain observations to dysfunction claims, and (v) articulate potential falsifiers. Finally, it argues that neuropsychology’s greatest pedagogical contribution is not a catalog of deficits but a logic of inquiry: natural experiments reveal the normally invisible computational and representational work of the nervous system, thereby reframing ``what is wrong?'' into ``what must the intact system do to make ordinary experience possible?''