The church is an authority on knowledge in the Middle Ages. During this period, there are different beliefs compared to modern beliefs; the earth is 6000 years old (1), the man is not an animal (2), the sun revolves around the earth (3), thinking takes place in the immaterial mind (4), the Greeks knew everything (5).

The belief that the Greeks knew everything led to the emphasis on the preservation of knowledge rather than the generation of new knowledge in Europe. However, science flourishes in the Middle East (e.g. mathematics and physics). The Middle East introduced Europe to Aristotle again in the 13^th century. After Aristotle’s rediscovery, his knowledge was presumed to be correct until Galileo refuted some of his knowledge, proving that Aristotle was fallible.

Augustine of Hippo was a scientist from Algeria in the Middle Ages:

• Formulates the first theory on learning.
• Discovers the unconscious
• Identifies the problem of other minds

He introduces the argument from analogy as a solution to the problem of other minds and this problem is still relevant in modern science (e.g. AI research).

In Europe, during the Middle Ages, people believed in the Ptolemaic system, the idea that all celestial bodies orbit around the earth. This is a flawed model as it requires epicycles in order to explain retrograde motion, making this model mathematically complex. The heliocentric model, developed by Copernicus, refers to the idea that all celestial bodies orbit around the sun.

Copernicus published his book promoting the heliocentric model very late because of a fear of the church’s reaction (1) and because of uncertainties about his model (2). There were several objections to Copernicus’ heliocentric model:

• The model does not explain the data very well.
• The model does not explain why entities are not thrown into space if the earth is moving.
• The model does not explain why a stone falls straight down if the earth rotates.
• The model does not explain why the moon is not orbiting the sun.
• The model is mathematically as complex as the Ptolemaic system.

The mechanistic view is the worldview according to which everything in the material universe can be understood as a complicated machine.

Galileo Galilei has several important characteristics:

• Defends the heliocentric model using experiments; he disproves counter-arguments to the heliocentric model.
• Disproves Aristotle on several occasions.
• Recognized the value of experiments; he recognized that artificial conditions provide insight into the natural world.
• Proved the existence of moons at other celestial bodies.
• Recognized the value of using instruments to aid observation.
• Had a conflict with the Roman Catholic Church.

In the Middle Ages, the idea that instruments could be better than the naked eye is revolutionary. The idea. The value of experiments is still relevant in modern science, as there are still discussions about ecological validity. Galileo’s conflict

Wolff has several important characteristics:

• Proposes rational psychology; in this type of psychology, axioms had to be derived from fundamental disciplines.
• Proposes empirical psychology; in this type of psychology, the demonstrations of rational psychology had to be considered.
• Introduces introspection as a scientific method

Introspection refers to the study of the mind by using the mind (i.e. investigating one’s own mental states).

According to Comte, introspection is not a reliable observation as there is no difference between the observer and observation (1), objectivity is impossible because it is not possible to control results (2). The results from introspection are not public, which goes against scientific principles of positivism. Comte believed that the mind could only be studied scientifically through physiology.

According to Kant, introspection is not a good method as mental states do not have quantitative properties (1), consciousness never stands still and can thus not be observed at a single point in time (2), the observation of the mind changes the mind (3) and introspection cannot provide mathematical descriptions (4).

There were three problems with studying man scientifically:

1. It was believed that man could not be described mathematically.
2. It was believed that man was not an animal.
3. It was believed that the mind is immaterial.

The mind can be described mathematically, as mental chronometry – the study of reaction times of mental operations – provides a mathematical description of mental processes. This was demonstrated by Von Helmholz, who discovered the speed of transmission in the nervous system and Donders who studied the duration of mental processes.

Quetelet proposed that statistics should be applied to humans because individuals could not be lawfully described but groups of people can, resulting in quantitative sociology. The noise in research into humans – the result of humans being stochastic – allows for a quantitative approach in psychology. Fisher demonstrated that confounds could be factored out in statistical analyses.

Weber discovered that the fingers are the most sensitive body parts by investigating the limits of the tactile senses. He also demonstrated the importance of muscles and joints for weight discrimination. Fechner was inspired by Weber and realised there could be a Newtonian mathematical function connecting the magnitude of the sensation to the magnitude of the stimulus, birthing psychophysics.

In short, Von Helmholz (1), Donders (2), Quetelet (3), Fisher (4), Weber (5) and Fechner (6) demonstrated that humans could be mathematically described.

Darwin has several important characteristics:

• Introduces the theory of evolution; the origin of species is based on accidental mutation (1) and natural selection (2).
• Introduces the notion that man is an animal.
• Proposes that human and animal behaviour can rest on the same explanatory principle as it is both mediated by evolutionary pressure.

The two processes of Darwin’s theory make that evolution is a blind and fully automatic system driven by a statistical principle.

Ancient Egyptian physicians knew the importance of the brain in behaviour as was shown by the Edwin Smith Papyrus. Plato believed the soul consisted of three parts and the brain was the most important part.

Aristotle, on the other hand, believed that thought was located in the heart because of the heart’s central location (1), its importance for emotion (2) and because all living organisms have a heart (3). According to Aristotle, the function of the brain was to cool the heat of the heart.

Galenus discovered a function of the nerve pathways and established the role of the brain as the hub of behaviour. He believed the brain communicated with the body through ventricles (1), animal spirits (2) and nerves (3). Vesalius created a functional division for the ventricles; common sense and fantasy (1), thoughts (2) and memory (3).

Descartes introduced mechanical ideas and viewed other organisms as automatons. His mechanical theory of reflex states that a sensory sensation travels through the nerves (1), this is bounced back like a mirror (2) and this leads to involuntary behaviour (3). According to Descartes, the soul remained spiritual in nature and the body and the soul interact in the pineal gland.

Gall founded two different subdisciplines:

1. Organology
   This is the view that differences in predisposition can be seen in cortical development.
2. Cranioscopy
   This is the view that differences in cortical development can be seen in nodules of the skull.

Spurzheim formulated phrenology. Willis proposed that higher brain structures existed for more complex organisms and allowed for more complex functions and that the lower structures allowed for elementary functions. This means that a more complex animal has more brain structures and a less complex animal only has the lower brain structures.

In the 19^th century, there are five breakthroughs which altered the model of brain functioning:

1. Discovery of the cerebrospinal axis
   This is the finding that the body remains functioning when the cerebral hemispheres are disconnected and thus that many bodily functions do not require the cerebral hemispheres.
2. Growing impact of the reflex
   This is the finding of the reflex arc (Hall). Procháska proposes that reflexes were controlled by the spinal cord and Sechenov proposes that thinking is a reflex of the brain.
3. Localisation of brain functions
   This is the finding that brain functions could be localised and gave rise to the localisation theory. This theory gains strength through Jackson, Broca and Wernicke.
4. Discovery of the nerve cell
   This is the finding that the brain exists of separate cells. This was aided by better microscopes (1) and improved techniques to stain the brain tissue, which allowed neurons to stand out (Golgi) (2).
5. Disentangling of the communication between neurons
   This is the finding that nerves could be influenced by electricity (Galvani) (1), the finding that neurons communicate using electricity (Bois-Reymond) (2), the

Mental health treatment was seen as a medical treatment before the second world war, explaining why psychologists were not allowed to treat patients without supervision. After the second world war, there was an increased need for psychological help (e.g. shellshock patients) which led to a more psychological approach to mental disorders.

After the second world war, there was the rise of antipsychiatry (1), treatments requiring scientific evidence (2) and medication being used for mental disorders (3).

People tend to believe that mental disorders are rooted in the brain as a result of psychiatry’s origin in medicine. This view was strengthened by the discovery that certain drugs can alleviate the symptoms of mental disorders.

Charcot and Freud started to see psychiatric symptoms as expressions of diseases, positing psychological factors as the causes of symptomatology. Neurosis refers to unconscious conflicts which express themselves in symptomology.

Rogers introduced humanistic psychology based on the acceptance of patients. In humanistic psychology, a good therapist has unconditional positive regard (1), empathetic understanding (2) and congruence. Congruence refers to the therapist being genuine in his support and understanding. Cognitive behavioural therapy is based on a psychological approach to mental disorders.

The medical and psychological view of mental disorders naturalizes mental disorders as they both view mental disorders as a part of nature which can be systematically studied and understood. This got rid of supernatural explanations for mental disorders.

Extreme naturalization refers to the idea that mental disorders deviate from the norm and that the norm itself might be flawed rather than the patients. Antipsychiatry states that mental disorders do not exist and only norms for normal exist. However, increasing prevalence of mental disorders might indicate a change in society rather than a change in people.

The psychological test is an instrument that probes a person and the person’s response is used to infer a psychological state or attribute. It needs to take reliability (1), validity (2), bias (3) and random measurement error (4) into account. A test contains the condition of intent (1), is administered as an indication of some condition (2) and involves a difference in status between the test-giver and test-taker (3).

There are three types of psychological test:

1. Authenticity test
   This is a test to determine whether a person is genuine and to determine whether a person is guilty or innocent.
2. Qualifying test
   This is a test to determine the fittest person for a particular task.
3. Diagnostic test
   This is a test to determine which condition a person suffers from.

An achievement test (i.e. the form of the qualifying test) is a standardised test which measures the knowledge of a particular topic or set of topics. Tests were created to prevent bias and unfairness as tests are more reliable and less biased than teacher judgements.

Meritocracy refers to a society based on ability. Educational tests serve meritocracy

The scientific method is used because it allows for systematicity and accumulation of knowledge (1), it makes use of well-defined methods (2), it provides clarity (3), it is useful for predictions (4) and it makes knowledge revisable (5). However, there are several reasons why psychology might not be a science:

• Society does not always see psychology as a science.
• Practitioners tend to rely on clinical intuition rather than scientific research.
• It is not always believed that the mind can be studied using the scientific method.
• Scientific claims are often exaggerated and fallible.

Dilthey criticized scientific psychology:

• Psychology should be content-based
  The focus of psychology should be on what the mind comprises rather than on how the brain functions.
• Psychology should study human experience in its totality
  There should be a holistic approach to the mind rather than a reductionist approach.
• Psychology should study the mind in context with the person
  The mind should not be studied in isolation but in context with the person.
• Psychology should use understanding
  The focus should be on understanding the mind rather than explaining the mind.

There are three levels of understanding according to Dilthey:

• Elementary forms of understanding to solve the simple problems of life.
• Empathy through which an observer can re-experience someone else’s experiences.
• Hermeneutic level of understanding in which the observed person can be better understood than the person understands himself.

Critical psychology refers to a movement in psychology that criticizes mainstream psychology for failing to understand that knowledge does not refer to an outside reality and that scientific knowledge is not cumulative but consists of social constructions. Social constructivism states that knowledge is a social construction. According to social constructivism, it is difficult to say whether knowledge is cumulative, thus theories should not be judged on truth but on their ability to generate new openings for action.

Constructivism comes with a responsibility as the questions and categories that are deemed more relevant are more important as it is not possible to hide behind the idea of revealing the truth. Sokal demonstrated the political consequences of a relativist view.

There are several points of criticism towards experimental psychology:

• Experimental psychology neglects individual differences.
• Experimental psychology makes use of WEIRD samples.
• Experimental psychology’s research question is determined by the methods available.

Feminist psychology made several objections to traditional psychology:

• Men are taken as the norm and women deviate from this norm.
• Men are deciding what is worth investigating and how it should be investigated.
• There is a bias to publish results demonstrating differences between genders.
• The results regarding gender differences are regularly interpreted in line with stereotypical expectations.
• The results regarding gender differences are interpreted as due to the individual and not due to the social context.

There is a reciprocal interaction between psychological science and society. Aberrant cognition, affect and behaviour used to be explained by bizarre theories and the treatments were ineffective and inhumane. Each culture has a symptom pool and patients with psychological problems gravitate towards the symptoms that are thought to be a legitimate indication of a mental disorder. Clinical practice is changed by societal changes if these changes influence the symptom pool.

It is important to interpret psychological research with care because:

• Psychology is influenced by society (e.g. more multiple personality disorder diagnoses when it is portrayed more in the media).
• Psychological research is influenced by socio-political biases.
• The context in which researchers work is influenced by the socio-political context.
• Psychological research does not always replicate.

Systematic empirical psychology has led to scepticism regarding adventurous claims. One important function of psychology is debunking nonsense.

Psychological categories are not static but change because of research and societal influences. The categories are prone to subjective conceptions of what these psychological categories hold. Foucault states that scientific categories order society, making these categories political.

Hacking formulates the looping effect of social kinds which states that social kinds can start as arbitrary but acquire causal power in our social system. This occurs for psychological categories because they become part of people’s conceptualization of their own identity (e.g. “I act like this because I have ADHD”). Psychology shapes reality through the label it creates a society adapts to the label, making the label real.

Foucault states that society needs outcasts and mental disorders are used for this goal. Science employs psychology to exert power over the population through surveillance (e.g. psychological tests). Diagnosis of mental disorders steers social reality as people may interpret their behaviour differently after diagnosis. In addition to that, society treats people differently after diagnosis making the category real in a process of social interaction.

Several requirements allow others to evaluate claims and present counter-evidence. These requirements serve as demarcation criteria for science:

1. Knowledge needs to be coherent and cumulative (i.e. cumulative knowledge)
2. Knowledge needs to be made available (i.e. allows for cumulative knowledge).
3. Knowledge needs to be based on prediction and falsification (i.e. no ad-hoc explanations).
4. Knowledge needs to be revised in light of contradictory evidence (i.e. theory can be revised)
5. The exposition of knowledge needs to be clear (i.e. clarity of knowledge).
6. The information-gathering needs to use well-defined and widely accepted methods (i.e. allows for replication).

These requirements make scientific knowledge trustworthy. Scientific racism might exist through hidden racism; advancing one’s race by non-conspicuous biases against other groups.