Psychologism

2.2.2. The main period (1880–1920) and its three aspects

Kant is at the origin of anti-psychologism both in the field of epistemology, as well as in logic, since in both it establishes the fundamental distinction quid facti – quid iuris and separates issues of genesis and validity (Geltung). Now, while Kantian anti-psychologism in logic is going to be decisive, via Herbart, for nineteenth-century Platonism, Kantian anti-psychologism in epistemology is going to be decisive for Neo-Kantianism. In both cases, however, this does not happen directly, but through the mediation of other processes that take place in the nineteenth century and to which we have made reference (2.1). From Kantian anti-psychologism in logic, the Platonism present in the Psychologismusstreit is derived through the logische Frage (2.1.4), the logicisation of calculus (2.1.5) and, ultimately, the conflicting confluence of both processes; from Kantian anti-psychologism in epistemology, the Neo-Kantian is derived through the psychological method (2.1.2) and the discussion regarding Kant’s interpretation (2.1.3) linked to it.

With this, we call attention to a core aspect of the Psychologismusstreit: two trends must be clearly distinguished in it that although they both refer to Kant, they do so in two characteristically different ways, they have a relative degree of autonomy in their effective historical development and they are clearly distinguished by the thematic-systematic accent that anti-psychologism assumes in each of them. While Neo-Kantian anti-psychologism is exclusively epistemological, the anti-psychologism proper to logical realism, while remaining epistemological, is primary and characteristically logical and semantic.

From the status questionis established by Fischer-Meyer, it passed, with Neo-Kantianism, not only to the denial of the psychological method and all of Kant’s psychological reading, but also to the proposal of a positive alternative, also different from the speculative proceeding, namely, the transcendental method. The transcendental method consists of a reflection on the Faktum of science, considered as a logical-objective unit with a view to establishing its logical presuppositions a priori (Cohen, 1877: IV–VI; 1871 [1885]: 93; 1881 [1887]: IX–X; Natorp, 1912b: 196–7). An essential element of the Neo-Kantian conception of a priori is that it is not separable from experience because it is reduced to be its condition of possibility, there being, therefore, no place for a realm of abstract objects. Attending to the above is critical to understanding the fundamental difference between Neo-Kantian anti-psychologism and the one characteristic of logical realism, with which, on the other hand, it has numerous points of contact (anti-intuitionism, logicism). While, for logical realism, the postulation of abstract objects is essential and definitory of its anti-psychologism, for Neo-Kantianism, there cannot be an autonomous formal logic, since all logic is necessarily transcendental (Cohen, 1902 [1922]: 11; Natorp, 1911: 42–3). This transcendental logic, on the other hand, tends to absorb in some cases transcendental aesthetics. Whether this happens or not, anti-psychologism regarding pure forms of intuition becomes particularly relevant in Neo-Kantianism.

One of the classic and most influential forms of logical psychologism is found in Mill, who explicitly affirms the thesis that logic is part of psychology (1865 [1979]: 365). Mill’s psychologism arises from a radicalization of empiricism that ends up eliminating the Humean distinction amid relationships between facts and relationships between ideas. However, if Mill is a psychologist thinker with respect to logic, he is not so with respect to semantics, because in it he criticises conceptualism and its ultimate assumption, namely, the immanence principle (Mill, 1869: 15ff.; Godden, 2005; Skorupski, 1989).

Mill’s logic exerts a decisive influence on German logicians in the mid-nineteenth century. There are, in this, however, peculiarities derived from the logische Frage, which lead, on one hand, to his logical psychologism extending to semantics, on the other, to the base empiricist element tending to recede into the background vis-à-vis the relativistic consequence.

The emergence of a strong immanentist movement is a decisive factor for Bolzano’s platonising logicism to result in Frege’s militant anti-psychologism, which will refer primarily to this relativistic psychologism linked to the logische Frage (1893: XIXff.). Frege’s criticism of Mill, on the other hand, is basically directed at his mathematical empiricism, not at his logical psychologism (1884 [1988]: 19–23). Husserl’s anti-psychologism has strong points of contact with Frege’s, but also some peculiarities, since, while referring to the German logicians of the 1880s, Mill’s logical psychologism is a privileged target (1900 [1975]: 88ff.). Moreover, the main target of Neo-Kantian anti-psychologism were not the psychological logicians derived from the logische Frage, but the psychological method and, in particular, some variants of it, to which the Neo-Kantians were linked in their early days (Helmholtz, Völkerpsychologie) (Windelband, 1880: 393; 1884 [1907]: 319; Cohen, 1871 [1885]: 109; 1881 [1887]: IX–X).

The discussion around the Psychologismusstreit in Husserl extends decisively in the second volume of Logische Untersuchungen and moreover, accompanies its subsequent development as a whole, presenting a new and peculiar chapter with the turn of phenomenology to transcendental idealism and the introduction of the idea of ‘reduction’. With this, a new variant of anti-psychologism is established, different from the previous ones (Husserl, 1906–7; 1913b).

Although it is not usual, based on our current knowledge of the issue, a fourth anti-psychological variant linked to the realism of Brentano and his school could still be further distinguished (Brentano, 1874 [1971]: II, 181–8; Marty, 1908: 12). Based on the principle that judgement is the bearer of truth and that logic, therefore, deals with judgement, it denies that Platonism and transcendentalism are necessarily the only alternatives to psychologism.

The German Psychologismusstreit ends up reverberating in various ways in England and France, where it gives a new dimension to autochthonous psychologism tendencies and relocates them in a new context. With a slight temporal lag, the question of psychologism is raised in England with characters similar to Germany. Thus, on one hand, there is a chapter of the Psychologismusstreit linked to the interpretation of Kant (Green, Caird, Sidgwick), on the other, an echo of German logic, in particular that of Lotze and Sigwart (e.g. Bosanquet, 1888), no less than a critical reception of German psychology trends from Herbart to Brentano (Ward, Stout). From Bradley (1883: 2ff.), a distancing from psychologism is announced that, decisively passing through Stout (1893: 109ff.; 1896: I, 40ff.), reaches maturity with the platonising tendencies of Moore (1899, 1903) and Russell (1895, 1899, 1903). Characteristic of this process is that the semantic aspect assumes priority, on one hand, and, on the other, this semantics has clear referential and anti-intentionalist lines. In France, the question of psychologism, which is announced early in the controversy between Broussais/Comte/Leroux and Cousin/Jouffroy (Braunstein, 2012), acquires a new impetus and a new dimension with Couturat (1906) and his reception of the new trends of island philosophy.