Common sayings, proverbs, and folk wisdom represent a repository of everyday psychological knowledge. The organization of such collections often distinguishes between statements based on context or main themes, implying that their utility is context-dependent. A key characteristic of everyday knowledge, including psychological insights, is its indifference to logical consistency. Proverbs frequently contain opposing statements, highlighting that folk wisdom does not prioritize logical coherence. This empirical validity is not derived from logical deduction.

An analogy can be drawn from the educational process of Pinocchio by Malvina. When asked how many apples would remain if three were given to Artyom, Pinocchio, operating within the framework of everyday knowledge, responded that he would not give any apples away, rendering the question about remaining quantities irrelevant. This illustrates empirical validity, which is unconcerned with logical frameworks. For instance, the advice "Measure seven times, cut once" contrasts with "He who does not risk, does not drink champagne." These statements, while contradictory, are valid within their respective contexts.

In contrast, scientific knowledge is organized around verifiable hypotheses. A scientific hypothesis is a conceptualized idea that can be empirically tested. Scientific inquiry is limited to phenomena that can be experimentally verified. While many psychological phenomena are intriguing, they may not yet be amenable to empirical testing.

A notable anecdote involves Ivan Pavlov, who reportedly dismissed laboratory staff who attributed thoughts or feelings to experimental animals. This practice stems from the use of everyday language ("thought," "felt," "remembered") which is not empirically verifiable. While such descriptions are common in casual conversation about pets, they lack scientific rigor. Pavlov's stance underscores the requirement for verifiable hypotheses in science, which must form a logical system, as scientific endeavors do not permit logical contradictions. Science, therefore, can be defined as a logical system of verifiable hypotheses. Scientific psychology adheres to this definition.

The reproduction of knowledge, or its transmission to others, is fundamentally similar to its initial acquisition in everyday life. However, everyday knowledge often fails to account for the conditions under which it was acquired, neglecting context. This is exemplified by the English ballad, retold by Samuil Marshak, about a son who misinterprets his mother's instructions due to a lack of contextual detail, leading to inappropriate behavior at a funeral and a wedding. Consequently, everyday knowledge can only be effectively reproduced when an individual encounters a similar specific situation. The absence of contextual consideration hinders knowledge accumulation and the utilization of past experience. While collections of folk wisdom exist, their direct application is limited without personal experience in a comparable situation. The persistent "generation gap" can be partly attributed to this phenomenon, as each generation must navigate life's challenges anew.

Science, however, aims to make this life path more productive by ensuring the full consideration of conditions during knowledge reproduction. Scientific articles, particularly in experimental psychology, are structured around verifiable hypotheses. These hypotheses identify variables and their relationships, distinguishing between correlational and causal links. Crucially, they also enumerate all potential influencing factors, even unexpected ones. This meticulous approach facilitates the accumulation and consolidation of knowledge. Engaging with scientific postulates and hypotheses allows individuals to build upon the accumulated experience of others, as articulated by biologist Claude Bernard: "We are pygmies standing on the shoulders of giants," where the "giants" represent accumulated scientific knowledge, accessible due to the detailed description of the conditions under which it was obtained.

The Specificity of Scientific Psychological Knowledge

Wilhelm Wundt initially sought to establish psychology as a natural science, akin to physics in the mid-19th century. He focused on identifying elements of consciousness and their interconnections, drawing parallels with the concept of the indivisible atom. However, Wundt recognized that psychology could not be solely a natural science; it must also be a humanitarian science. This duality arises because a science of human beings inherently involves humanistic aspects.

In natural sciences of the mid-19th century, the focus was on subjects devoid of internal activity. Applying this to psychology, it meant studying entities without what might be termed "soul" or free will. The introduction of such elements would invalidate naturalistic models, as an "atom with a soul" could act unpredictably, rendering scientific constructs obsolete. Psychology's inherent tension lies in its aspiration to be a natural science while remaining fundamentally humanitarian. Wundt acknowledged this, proposing two branches of psychology.

The first, termed "explanatory psychology," aligns with the natural science model, allowing for hypothesis formulation and experimental verification. The second, "descriptive psychology," addresses phenomena that cannot yet be explained or experimentally investigated. This branch focuses on description, as exemplified by Wundt's multi-volume work, "The Folk Psychology of Peoples," which details customs, beliefs, and sociocultural norms of various groups, areas where direct experimentation is not feasible.

A guiding principle for psychological science, reflecting its unique nature, is that the human being is both the knowing subject and the known object. Unlike in natural sciences where humans are primarily subjects, in psychology, they are also objects of study, possessing internal activity. This is evident in psychological testing, where participants may intuit the test's purpose, sometimes more effectively than the test designer. A humorous definition of a test suggests that "tested intelligence is the tested intelligence of the one who created the test," implying that a participant's insightful response can reveal more about the creator's intellect.

This principle leads to two significant consequences. The first consequence, applicable to all sciences but particularly pronounced in psychology, is that a psychological fact is dependent on the researcher's interpretation.

Example 1: Investigation of Skin Sensitivity

Consider the measurement of human skin sensitivity, typically involving touching the skin with two points of a compass-like instrument and asking the subject to distinguish between one or two touches. The threshold at which two touches are perceived is recorded. In the late 19th and early 20th centuries, researchers aimed for "pure" data, studying isolated memory, perception, or thinking. The prevailing view of a sensory organ was that of an information receiver. To obtain pure data on skin sensitivity, the hand was immobilized, often in plaster, to isolate the sensory input.

By the mid-20th century, the understanding of sensory organs evolved. They were recognized not merely as receivers but as active explorers of reality, equipped with motor apparatus. Without movement, sensory perception diminishes. For instance, a light stimulus on the same spot of the retina is perceived for only 2-3 seconds without eye movement. Consequently, the practice of immobilizing the hand in plaster was abandoned. Removing the hand from the cast led to a recalculation of sensitivity, revealing it to be 5-6 times higher, a more naturalistic finding.

Example 2: Jerome Bruner's Research

Jerome Bruner, a student of Jean Piaget, conducted research in developmental psychology, focusing on the cognitive abilities of infants. Bruner initially aimed for precise scientific data and reasoned that the infant's mother should not interfere with the study. He conducted experiments with infants separated from their mothers, observing unexpectedly low cognitive performance. Bruner later realized his error: the infant's existence in the first year of life is intrinsically linked to the mother, who represents a vital condition for development. Studying infant capabilities required the mother's presence. When mothers were included in the experimental setting, the infants' cognitive performance significantly improved. This demonstrates how altering the interpretation of the research unit—the infant within its maternal context—changed the factual data obtained. The conclusion remains: psychological facts are contingent upon the researcher's interpretation.