Kant´s Notion of a Transcendental Schema. Lara Scaglia

added by the activity of understanding and fantasy, which have the tendency to go beyond experience, thus generating illusions and mistakes.

      Christian Thomasius provides another - and highly interesting for our purposes - epistemic use of the noun ‘schema’. According to him, cognition begins with the influence of the objects on our senses, which leads to the constitution of schemata, regarded as a kind of Cartesian material ideas as the basis of cognition:

“Thinking is an act of the mind, in which man - or the mind in the brain – through schemata impressed in the brain by the movement of external bodies via the sensible organs, affirms, negates or asks for something, through discourse and constant words of orations.” (Thomasius 1688, pp. 83–84, transl. L.S.)¹⁸

      This process through which ideas are constituted is not only passive, but also active, as can be seen from what Thomasius attributes to the faculty of understanding:

“[…] but we must not forget also their Entium rationis, that have the only and unique essence within human understanding. These are nothing more than the expressed schemata or ideas of actual things and their unification or separation, which are realised through the understanding. When the understanding joins together the same ideas and ←29 | 30→separates the different ones and gives a place to each one, this is called ens logicum or metaphysicum.” (Thomasius 1691, pp. 131–132, transl. L.S.)¹⁹

      Since no schema is possible without the activity of the understanding, material ideas can be described as the first elements implied in the process of cognition, constituted both by passivity (the matter provided by the external world) as well as activity (the unification and diversification of the understanding):

“§ 13. Because the truth is nothing more than a coincidence of the human mind and the nature of things outside those thoughts. § 14. Here you have not to ask whether the mind must or must not correspond to things […] § 15. For the things are such that they can be understood by humankind and the mind is made in a way that it can grasp the external things. § 16. The external things cause impressions on human understanding. This, then, considers these touches, separates them and puts them together.” (Thomasius 1691, pp. 139–140, transl. L.S.)²⁰

This theory shares similarities with Kant’s (as well as the Lockean²¹) perspective: firstly, all assert that the process of cognition begins from the senses; ←30 | 31→secondly, they underline the necessity of both passive and active faculties; thirdly, they describe the activity of understanding in terms of unification and separation and finally, they define the role of the schemata as functions in the middle between passivity and activity. As Psilojannopoulos (2013) states²², these theoretical similarities with the doctrine of Kant are also reflected in terminological ones, thus providing circumstantial evidence to the claim that Kant knew Thomasius’ Einleitung zu der Vernunftlehre²³.←31 | 32→

      Later on, the term can be found in the works of Christian Wolff, who uses it not in an epistemic, but rather in the more common figurative sense, namely as a framework to represent a relation. More specifically, he refers to relations among relatives through a “schema of parenthood” - “schema cognationis”- (Wolff 1747, pp. 416–17).

In contrast to Wolff, his disciple Joachim Georg Darjes²⁴ uses the noun with a meaning connected to material ideas. Like Thomasius, he explains the process of cognition, stressing that the spontaneous being (the soul) is affected by external things, which leave material ideas in the brain. To have ideas, a medium between the soul and the external substances must be presupposed, that is the schema (Tonelli 1994): “[…] this schema of perceptions, mentioned above, is the only link of passive and active entities.” (Darjes 1743, par. 326, transl. L.S.)²⁵

      The soul, which is a simple and purely active essence, is affected by the senses thereby producing perceptions materialiter spectatae (Darjes 1743, par. 124) but for cognition to arise, these perceptions need to be moulded by schemata, which are mediating functions between the active soul and the passive sensibility. Then, through a process of confrontation and abstraction, general concepts can be produced by the soul’s operation. Cognition, therefore, begins with the senses, with the experience of single objects and then develops through processes of abstraction led by the understanding’s activity through attention and reflection (Psilojannopoulos 2013, pp. 252–253; Lorini 2011, p. 282). In this interpretation of the concept of schema as a medium between the receptivity of the senses and the activity of the understanding, we can see Darjes anticipating an important aspect of Kant’s account. More specifically, Darjes describes here what Kant discusses when he considers concrete, empirical examples of schematising concepts.

      Besides this epistemic connotation, the use of ‘schema’ in the philosophical literature of the modern age is still linked to the arts of rhetoric and speech, as it is stated in the Encyclopedie, where ‘schemata’ are seen as instruments of the mnemotechnique, methods used to increase the capacities of memory.

“[…] because for sure our imagination is of great help to our memory, it is not possible to reject the method of schematisms, given that images have nothing extravagant or puerile about them and that they are not applied to things which are not amenable to them.” (Diderot & d’Alembert 1751–1780, transl. L.S.)²⁶←32 | 33→

Differently, namely in reference to biology and physiology, ‘schema’ is used by Ploucquet to indicate the body’s organisation, thus underling once again the function of schemata as a medium between activity and passivity: a body is a material entity provided with an activity giving it organisation: “[…] experience teaches and [the faculty of] reason deduces that bodies are organised in themselves and have a natural capacity to modify themselves in others schemata.” (Ploucquet 1764, par. 399, cap. XVI, transl. L.S.)²⁷

But aside from these rhetorical and biological connotations, the term is used again epistemologically by Johann Nicolas Tetens. In his Philosophische Versuche²⁸, a work which was open on Kant’s desk when he was writing the Critique (as Johann Georg Hamann²⁹ states in a letter to Johann Gottfried Herder on 12th May 1779). Tetens, often called the “German Locke”³⁰, deals among other things with the relation between the soul and the body and the sources and development of human cognition. He follows Darjes’ terminology of a ‘schema perceptionis’³¹, but regards it as a physical centre of unification of all the data of ←33 | 34→experience, referred to as “material ideas”: “[…] with each manifestation of the soul a certain inner part of our body acts; we can call this part the brain, sensorium commune, the organ of the soul, schema perceptionis or what else.” (Tetens 1777, II 158, transl. L.S.)³²

Schemata are regarded as synonyms for sensorium commune or “organ of the soul”, expressions possibly influenced by Charles Bonnet (quoted several times by Tetens) and meant to identify the part of the brain in which ideas are traced and combined. In his L’Essay de Psychologie (1755), Bonnet describes the natural production of ideas from infancy and states: “ideas are nothing but natural signs, and these signs