I am interested in psychology and psychiatry but often a counter argument given by others when I bring up this topic is that since each person is different mentally, there can't be a general all encompassing theory. In response, I agree to what they say and say that it is the same case with medicine. All our physiologies are technically different in slight ways from each other, but still similar enough to be studied, but, this argument is a bit weak since the idea of the mind and processes relating to it is on a more abstract level than that of our physical body.

What would be a stronger counter argument in defense of psychology and psychiatry?

  • $\begingroup$ I personally cannot come up with a stronger argument, but I can't prove that so hence the comment. If you work with trauma like I have you will quickly see the fact that not everyone reacts in the same way to trauma. PTSD experiences will involve different triggers for anxiety, panic attacks and flashbacks. Therefore, their anxieties will be different. That is just one small example of how things are different from person to person $\endgroup$ Commented Nov 20, 2021 at 10:33
  • $\begingroup$ What also do you mean by "in defense of psychology and psychiatry"? The argument that everyone is different and theories are untestable in the traditional scientific sense is in defense. Especially against those who try to downplay the study as non-scientific. See your other question on that $\endgroup$ Commented Nov 20, 2021 at 12:34
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    $\begingroup$ Every snowflake is different. Therefore it is impossible to have general theories about snowflakes. $\endgroup$ Commented Nov 21, 2021 at 1:36

2 Answers 2


From a neuroscientific point of view, our brains are really quite similar. Two mechanisms come into play during the brain's development: nature and nurture (the extent of each giving birth to a major debate over the years).

The "nature" part is our genome, which sets the ground rules. The genome means that our nervous tissue is always made of the same types of cells: neurons and glia. Additionally, from a developmental biology point of view, a human embryo develops the same way across individuals, and this is the case for brain development as well. This results in a similar structure of the brain: we all have the same components, arranged roughly the same way. We all have a cerebellum, a cerebrum, a thalamus, our cortex always has 6 layers, etc. This is the first source of variation: for instance, Einstein was reported to have many astrocytes (a type of glia) compared to average people. However, the variation is small enough to allow us to construct very comprehensive theories of the brain.

The "nurture" part is due to the brain's plasticity. Most of the wiring in the brain, its synapses, are formed as a result of a learning process. This is where most of the variation comes from. Fundamental mechanisms of the brain are similar between individuals: for instance, the primary visual cortex shows the same kind of retinotopy for everyone, the primary motor cortex the same kind of somatotopy, most memories are stored in neuronal assemblies which can be modeled as attractor networks (e.g. Hopfield networks) to enable retrieval, etc. However, the more you move up the cognitive ladder, the more differences start to arise. For instance, people can have vastly different personalities.

The pivotal argument, however, is that we start with almost identical "hardware", and the "software" is a result of processes which can be generalized among groups of people, leading to a great deal of commonality among people, thus allowing theories to be constructed, abstracting away some of the myriad idiosyncrasies of each person. For instance, people who go through a romantic relationship are bound to react in a way that presents common aspects.

To sum it up, the more you move up the cognitive ladder, the less general rules you can come up with, and the more complex theories get.

  • $\begingroup$ An interesting answer touching on the nature vs nurture debate. One bit that jumps at me initially is that you said "the more you move up the cognitive ladder, the more differences start to arise. For instance, people can have vastly different personalities." Very different personalities can be observed quite readily in different babies from a very early age. Are you saying that 10, 15, 20... babies given exactly the same environment for learning would have the same personality? Can you support that with references? $\endgroup$ Commented Nov 23, 2021 at 15:02
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    $\begingroup$ @ChrisRogers I think by "cognitive ladder" they're putting things like neuromuscular junction physiology low on the ladder, with minor individual differences (outside of pathology at least) and personality at the top, with larger individual differences. $\endgroup$
    – Bryan Krause
    Commented Nov 23, 2021 at 15:08
  • $\begingroup$ @ChrisRogers What Bryan Krause said is what I meant, the larger the scale, the more the emergent properties of the brain start to diverge. However, the idea of giving babies the same environment for learning and analyzing the resulting convergence/divergence of psychological characteristics is exactly the idea of controlled rearing experiments, one of the experimental tools at our disposition to investigate the impact of nature vs that of nurture. I can provide some specific references if you wish. $\endgroup$
    – David Cian
    Commented Nov 23, 2021 at 15:18

Over the past few decades developmental systems approaches to psychology, encompassing relational systems, embed nature and nurture, or organism and context, accommodating for a unique developmental trajectory for each individual. There are many approaches to developmentmental systems theory. Bronfenbrenner's bio-ecological model (incorporating both proximal and distal levels to that of the individual), and Sameroff's transactional model (emphasizes transactions between organism and environment) are two.

Moreover, Lerner (2018) explains that “the mutual embeddedness of organism and context” follows that a person’s “natural attributes” can influence an infinite number of developmental outcomes based on the variations of context and time. Similiarly, Schneirla’s work helped to advance this discontinuous framework for development (Schneirla labels as probabilistic epigenesis).

One way Schneirla advanced his probabilistic epigenesis view that supports discontinuity between levels of nature and nurture, is by proposing the idea of the structure-function relationship. In human development especially, our behaviors and thoughts (function) cannot be reduced to the characteristics of specific areas in the brain (structure). Rather, Schneirla explains that humans show brain plasticity, that is, an ability to respond differently to the same input.


Lerner, R.M. (2018). Concepts and Theories of Human Development (4th ed.). Routledge. https://doi.org/10.4324/9780203581629


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