Definition of
   a priori






The brain structures our opinion about the world through concepts /class, set, assemblage, Form, universal/ which hence constitutes a basal part of our thought processes. For instance, almost every word expresses a concept.


In the conversation below, the words signifying concepts are underlined

- Look out over this beautiful landscape! What do you see?
- I see some houses, a field and a lake. It is nice.




The discussion on this website differs from modern discussions (see below).

It is clear that concepts are not only created by humans, but also by other animals and maybe also by insects. A complex mechanism is hence not especially credible.


The link between "concept" and "reasoning" that is proposed at this website, i.e. that the brain create concepts through similarity, contrast, and/or contiguity, seems to be absent both within modern philosophy and psychology.


Created through reasoning


A concept /category, collection, aggregate, class, set, selection, essence, inductive conclusion, universal, Form, a priori cognition, a priori intuition/ is formed through reasoning that includes several premises.

The premises are, as always, related, and created through perception, from a memory (also based on perception), or from memories of conclusions from earlier argumentation.

Examples of concepts:
Apple, Large, Bicycling, Love, Ethics, the Whole.


The concept "apple"

When we say "apple", we do not mean a special apple ("the apple") but we mean our concept "apple".

It is created through synthesis between objects with related properties that separate apples from other concepts, e.g. pears. It implies e.g. a compilation from several apples including their size, colour, texture, the special oval form at the top and the remains of the apple blossom at the bottom.

modified from Valeriy Evtushenko,


How does the brain store a concept?


Is a concept stored as a network of partially forgotten perceptions (like the network at the page Synthesis)? Or is it stored as a hypothetical singular memory (one of the points in the network)?

fMRI investigations support that concepts continuously are recreated by the brain. Several areas in the brain, and not only one point, are activated during thoughts of a concept. Thus is, e.g. during thoughts of the tool "hammer", not only centres dealing with the tool's form are activated, but also centres for movements [e.g. Beauchamp].

This is called "embodied semantic cognition" [e.g. Rogers] within the field of semantic understanding.

Another demonstration of that we use large networks comes from when we remember that we have dreamt, but not what the dream was about. It is then sufficient with a single clue to the dream, and suddenly we are in contact with the complete network of associations that builds it.


It is only when we realize the brain's incredible capacity that we may understand that has resources to synthesize all concepts that we use during almost all speech and thought.

The problem of this has, since the Greek Antique, resulted in that concepts are discussed as existing outside of the brain and that they have been "given" to humanity.


Single neurons

Studies with microelectrodes in the brain have shown that a network that describes a special concept is summarized in at least one neuron.

For one of the tested persons, the same single "Jennifer Aniston" neuron signalled when different images of just this actress was displayed [Quiroga].

According to my opinion this does not imply that the memory of J.A. "was present" in that neuron. Instead it signaled, or summarised, when the network J.A. was activated.


Concepts as premises

As claimed above, concepts may of course also be created through reasoning where the premises are earlier created concepts (that are ultimately created through perception)..

As adults we have created so many concepts that virtually every new concept is created from those we have created earlier.


Partially individual

Concepts are, through their perceived sources, partially individual.

A person that is hit in the eye by a thrown apple will associate this additional property to the concept "apple".


Concepts: Animals and bees


It is obvious that not only humans create mental concepts: When a dog sees another dog for the first time, it will immediately identify it as part of its concept "dog".

Maybe even insects use concepts:

Concept learning, described originally as a higher-order form of learning and considered a cornerstone of human cognition, is a capacity that can be ascribed to honeybees

Avarguès-Weber & Giurfa 2015 - Conceptual Learning by Miniature Brains,
in Margolis & Laurence 2015 - The Conceptual Mind, Ch.1, p.21.

We find that bees can count up to four objects, when they are encountered sequentially during flight.

Dacke & Srinivasan 2008 - Evidence for counting in insects, Anim Cogn 11, p.683-689.

Insects display a variety of phenomena involving simple forms of tool use, attention, social learning of nonnatural foraging routines, emotional states and metacognition,

Perry 2017 - The frontiers of insect cognition, Current Opinion in Behavioral Sciences 16 p.111-118.


Descriptivist / Cluster Account


As opposed to more recent discussions concerning concepts, the discussions at this website show similarities to what has been called John R. Searle's Descriptivist / Cluster Account:


associated with a name “N” is a disjunctive set of descriptions

the disjunctive set of descriptions that is associated with a name can vary from speaker to speaker and from occasion to occasion

Boersema 2009 - Pragmatism and Reference, p.3 and 48-49.




Most of the concepts that we use are not clearly demarcated from other. As said above they are partially individual since they are in part formed from subjectively experienced premises. Some examples are the terms "house", "politician", "love".

When the premises that form the concept are more clearly perceived it becomes better demarcated, e.g. "lake", "human", "watch".

There are also concepts where the forming premises have been perceived very clearly. For some of those a lot of work has been invested in creating distinguishable definitions, e.g. "the quantity one", "centimetre", "Sweden", "di-deuterium oxide".

A definition implies a meticulous specification of properties that describes and distinguishes a concept.

When a definition describes a concept in such a manner that it cannot be confused with some other, the credibility of this term becomes so high that a rationalistic philosopher may be tempted to claim that it is known a priori:

... all analytic propositions are still a priori judgments even if their concepts are empirical, as in: Gold is a yellow metal ... .
I need no further experience outside my concept of gold, which includes that this body is yellow and a metal

Kant 1783 - Prolegomena §2.b (Hatfield, Cambridge 2004, p.17.

Kant hence claimed that the concept "Gold" only includes the perception "yellow metal".

But it may also include additional concepts, e.g. the material in the ring displaying that you are married, financial security, indestructability, greed, and Pizzaro's room with gold 1532 CE.

Also contemporary writers confuse concepts with definitions.


Concepts and definitions may change

Because concepts and definitions are ultimately based on perception, they may be altered, and the probability of this change depends on the type of concept.

The amount "one" will probably never be altered, while the concept "human" maybe need to be supplemented, for example in case future almost similar creatures would exist, e.g. "humanoid replicants" [from movie 1982: Blade Runner].

Replicant Rachel in Blade Runner: public domain
Replicant Rachel (Blade Runner 1982)

Opinions about concepts


Modern discussions concerning concepts are voluminous. Some contemporary examples are [Margolis & Laurence 2015, Carey 2009, Machery 2009]. A review can be found on the web [Margolis & Laurence 2017].

Plato's influence is obvious and the area sometimes has landed in infertile corners. An example is the term "universal" which on this website (and for Aristotle) merely implies an abstracted concept, i.e. an abstraction.

Now of actual things some are universal, others particular (I call universal that which is by its nature predicated of a number of things, and particular that which is not; man, for instance, is a universal, Callias a particular).

Aristotle - De Interpretatione §7, 17a37.

Some citations

Human beings, and only human beings, create deep, explicit, conceptual understanding /however, see above/.

As the rationalists insisted, there are innate input analyzers that compute perceptual representations.

Carey 2009 - The origin of Concepts, p.447, 448.

The evidence recounted above from infant psychophysics experiments provides a clear picture of the postnatal starting point and the transition toward development of object knowledge in humans subsequent to birth.

Johnson - Building Knowledge from Perception in Infancy, i Gershkoff-Stowe 2005 - Building Object Categories in Developmental Time, Kap.2, p.57.

I will be concerned, especially, with how the extensions of new substance concepts, acquired directly on first meeting with their referents, are fixed.

Millikan 2004 - On Clear and Confused Ideas, p.193.

The categorizations that humans make of the concrete world are not arbitrary, but rather are highly determined ... because the perceived world is not an unstructured total set of equiprobable co-occurring attributes. ...
categorization occurs to reduce the infinite differences between stimuli to behaviorally and cognitively useful proportions.

Rosch et al. 1976 - Basic Objects in Natural Categories, Cognitive Psychology 8, p.382-439.

three paradigms have successively emerged in the psychology of concepts: the prototype paradigm, the exemplar paradigm, and the theory paradigm.

Replacing the term “concept” with “prototype,” “exemplar,” and “theory” ...

Machery 2009 - Doing without Concepts, s.76 och 243-244.

concepts are mechanisms of detection, which allow us to track things, and which enable us to simulate them when they are not impinging upon our senses.

Prinz 2002 - Furnishing the Mind, Concepts and their Perceptual Basis, s.314.

The Classical Theory:
Most concepts (esp. lexical concepts) are structured mental representations that encode a set of necessary and sufficient conditions for their application, if possible, in sensory or perceptual terms.

Margolis & Laurence 1999 - Concepts, Core Readings, p.10.




Concepts have several interesting properties:

- They are very important for memory, reasoning and communication.

- They are created from several premises (that ultimately are founded on perception), which increases their credibility.


- With many, clear and credible premises the credibility becomes so high that they are considered as being "absolutely certain".

- They are partially individual, but are through human communication similar.

Beauchamp MS & Martin A - Grounding Object Concepts In Perception And Action: Evidence From Fmri Studies Of Tools, Cortex 43 (2007) s.461-468.
Carey 2009 - The origin of Concepts
Machery 2009 - Doing without Concepts.
Margolis & Laurence 2015 - The Conceptual Mind.
Margolis & Laurence 2017:
Quiroga RQ et al. - Invariant visual representation by single neurons in the human brain, Nature 435 (2005) 1102-1107.
Rogers TT & Cox CR - Neural Bases of Conceptual Knowledge, ch.4, s.62 in "The Wiley Handbook on the Cognitive Neuroscience of Memory", Wiley 2015.