Moreover, in a work wrongly attributed to Thomas Aquinas, the term ‘figura’ indicates the middle term which determines the structure of the judgement15.
Later on, William of Ockham and John Buridan also used the noun ‘schema’ to indicate the figure of the syllogism. More specifically, the former, in his Summa logicae (Ockham 1974) proposes to substitute Aristotle’s method to prove syllogisms’ figures (ekthesis) through the use of a particular syllogism (called expository), in which the middle term (which determines the form or schema of the syllogism) is the subject of both premises. While the latter develops in his Summulae de Dialectica (Buridan 1487) and in Consequentiae (Buridan 1493) a theory of syllogism, considered as a kind of formal consequence, distinguished in figures (or ‘schemata’), the conclusion of which might be direct or indirect (i.e. the minor term is predicated of the major).
This logical connotation of the noun endures in the Modern Ages also. However, it comes to possess also a new, epistemological sense, which later on develops and flourishes especially in the works of Kant.
Differing from the Middle Ages, the notion of schema in the Modern Ages returns to hold a variety of non-logical connotations: figurative (Wolff), rhetorical (Sturmius, Diderot, D’Alembert), biological (Ploucquet), physical (Bacon) and epistemic (Thomasius, Darjes, Tetens).
References to the use of the term are present in Rudolph Goclenius’s work (1547–1628) who relates it to ‘figure’ in two senses: first, in a geometrical sense and secondly, in a rhetorical one, which finds support in the work of Ioannes Sturmius (1507–1589), who defines ‘schema’ as argument, structure of discourse: “[…] schemata are arguments directed to prove and amplify, as similarities and examples.” (Goclenius 1613, p. 579, transl. L.S.)16←28 | 29→
A more philosophical connotation is attributed to the term by Francis Bacon, who uses the notions ‘schematismus’ and ‘meta-schematismus’ (Bacon 1620, I, pp. 45–5) to indicate the structure of matter and its changes:
“The human understanding is carried away to abstraction by its own nature, and pretends that things which are in flux are unchanging. But it is better to dissect nature than to abstract; as the school of Democritus did, which penetrated more deeply into nature than the others. We should study matter, and its structure (schematismus), and structural change (meta-schematismus)” (Bacon 1620, I, p. 51, transl. M. Silverthorne)17
In contrast with metaphysics, which looks for forms and essences beyond experience, he aims at elaborating a new method in philosophy, intended as an actual science, which works through the help of observations and experiments and aims to discover objective properties of nature. This last one is seen in its material process of formation (natura naturans), which has to be distinguished from all those characteristics (idola) 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
