Decorum is both criterion and principle of successful and cooperative communication within the scope of a persuasive communication model. It operates as a criterion due to its ability to ensure a suitable linguistic code and it operates as a principle due to its function as an ethical norm. Both in conjunction are prerequisites for a successful speech. The decorum is not understood as a predefined norm for every rhetorical situation, instead it has to be redefined each time. Thus, it necessarily has a relational quality which results from the situation itself and from the judgement of the recipient.

Decorum is understood as part of rhetoric in the sense of a civilian ethos which demarcates rhetoric against manipulation and propaganda.

Aptum refers to the appropriateness regarding the subject (lat. res) of a speech (inner aptum) and regarding the situation (outer aptum) of a speech. ¹

The term aptum is understood as a speech-immanent fit for example in relation to the emotions of the recipient.

„It defines the situational acceptance of values and bespoke codes. Appropriateness in rhetoric safeguards the process of persuasion insofar as it provides a basis for an accepted initial zertum (AZ) and initial codes (AK) in micro- and macrostructures from which persuasion can gradually evolve.“ ²

It describes the inner certainty (lat. certus) of the speaker as a starting point from which persuasion ensues.

A code refers to the rhetorical form of speech, the linguistic pattern and the rhetorical style of a message. It is due to these codes that style can be understood as the situational appropriateness. There are stylistic codes of the subject (aptum) on the one hand and on the other hand there are codes of ethics (decorum).

The term “norm” primarily means a social norm that describes the appropriate behaviour of all people involved and provides sanctions for deviation.

πρόσωπον denotes the face worn in public that contrasts with the soul (ψυχή) according to Plato (Alcibiades I, 130e3-5). (However, it is not the "face" that a speech is addressed to but the human soul.) Aristotle uses this term to describe the theatrical mask in comedy (Poetics 1449a36).

Persona is a rhetorical quantity that serves to shape a certain character or social role through the text. (It is to be distinguished from orator and ethos.) Cicero burrows this stoic term in De officiis from Panaitios and he deals “with the psychologically complex personality of human kind when he examines and determines the stratification of different roles (personae) that everyone plays in his life.” (S. 104)

The distinction a priori and empirical knowledge refers to the distinction of justification of “Urteile” (whether a judgement is true or false), whereas the analytical and synthetic distinction refers to the relation of terms (A/B).

A priori knowledge denotes knowledge which is independent of external experience → Knowledge by reason (before any experience)

Empirical knowledge denotes knowledge from experience such as the senses and empirical data → Knowledge by experience (Kant calls it “a posteriori” which means “after” or “in” an experience).3

The distinction a priori vs. innate knowledge: The first is not derived from experience but from reasoning alone, but the second is the knowledge you are simply born with such as Plato’s “Forms” or Chomsky’s “Universal Grammar”. Thereby, innate knowledge is a priori knowledge.

Kant’s definition of “synthetic a priori knowledge”: This kind of knowledge is found in natural science when the scientist goes beyond the concept of the matter. It describes knowledge that was gained by the predicate B which is not logically inherent to the subject A (synthetic) and gained by thought alone, not by empirical data for example. Humans think by using forms of perception and categories (quality, quantity, relation and modality). Thus, new knowledge is derived not from experience but from reasoning alone.

Etymologically, παρρησία stems from πᾶν (all) and ῥῆσις (speaking) and means „freedom of speech”.

There are several nuances of meaning due to its vast field of application in classical Greek from Euripides, Aristophanes, Aeschylus to the modern times of Foucault. It means „loquacious audacity” in line with Aeschylus and Plato4, but it could also mean „frank speech” with respect to truth (i.e. speaking the truth) in line with Plato and Aristotle.5

According to Foucault, someone who is using παρρησία is someone „who says everything he has in mind: he does not hide anything, but opens his heart and mind completely to other people through his discourse.”6

If translated directly, εὐδαιμονία means „good spiritual being”, derivated from the old Greek εὖ for „well/kindly/right” and δαίμων for „spirit, God or fortune”.

A δαίμων is a godlike creature in old Greek, a kind of guardian angel. Therefore, a εὐδαίμων is a creature that has the Gods on his side.

According to Aristotle, εὐδαιμονία is „something final and self-sufficient, [it] is the End at which all actions aim.”7 Man’s ἒργον (I, 6) is to live and do well and thereby rendering his life sufficient and happy (X, 7, 1178a5f.).

Qualia are mental states that constitute our phenomenal consciousness without having any functional (causal) role. Due to their intrinsic and irreducible nature, they are only experienced through introspection and are therefore private. By that they elude any form of physical explanation in an objective perspective (David Chalmer’s “hard-problem”)8.
Mental states and brain states are different: Mental states as qualia are of representational and intentional content whereas brain states are the neural activity of the brain.
Examples for qualia are falling in love, smelling the rain or desiring an ice cream.

The extension of a term is a set or classes of things to which the designated term corresponds and to which it extends to. It describes the range of applicability of a term in the world.

The intension of a term denotes the internal content of a term. It encompasses the attributes, properties or the quality of a term connoted by its definition.

„It is an old dispute whether formal logic should concern itself mainly with intensions or with extensions. In general logicians whose training was mainly philosophical have decided for intensions, while those whose training was mainly mathematical have decided for extensions.”9

The Aristotelian distinction of actuality (ἐνέργεια) and potency (δύναμις) appears in his Physics I, 8 as a reaction to the concept of the Eleatic school of Parmenides and Zenon that reject the idea of a thing becoming something from what is or from what is not and thus, only accept being in the pure sense as such: For what already is, cannot come to be and what is not, cannot come to be from nothing either. Aristotle disagrees by purporting being as a realization and a capacity: the basic notion of being as act and potency is born.

Aristotle wonders what actuality is in his Metaphysics IX, 6. What is the difference between “to see” and “have seen” or between a block of wood and a wooden statue?

Actuality                                 Potency

Reality                                     Potentiality

Determination of a thing          Power which can become reality

Form                                        Matter

Ex: to see                                 have seen

       wooden statue                  block of wood

An act (called „actus secundus” in scholasticism) denotes a being-at-work or being in activity as a realization of the capacity whereas potency represents the power or possibility. Actuality (from Latin agere / actus) realizes an innate capacity, i.e. it actualizes what it is by virtue of potency (lat. posse / potentia). Change is the passage from potency (block of wood) to actuality (wooden statue) in Aristotle’s way of thinking.


Potency   Actuality


¹ Heinrich Lausberg: Handbuch der literarischen Rhetorik. §§1055-1062.

² Sophia Vallbracht: Die normative Kraft des Decorum. S. 250.

3 Immanuel Kant: Critique of Pure Reason. B1, 2.

4 Aeschylus: Fragment 11a2-3 and Plato: Laws. II, 671b 3-8.

5 Plato: Republic 557b and Aristotle: Nicomachean Ethics. 1124b29.

6 Foucault, Michel: "The Meaning and Evolution of the Word Parrhesia", in: Discourse & Truth: the Problematization of Parrhesia. 2001, p. 12.

7 Aristotle: Nicomachean Ethics. I, 5, 1097b21f.

8 David J. Chalmers: "Consciousness and Its Place in Nature", in: Philosophy of Mind. Classical and Contemporary Readings. 2002, p. 247.

9 Bertrand Russell and Alfred North Whitehead: Principia Mathematica. Vol. 1, III, p. 72.