Main Philosophical Directions

Directions of Epistemological Theory

Subjective Idealism

If Leibniz's system was profoundly influenced by mathematics and the natural sciences, which endowed it with an objective character, the subjective idealism of Berkeley is firmly rooted in psychology. The soul, regarded as the only true substance, is given to us directly through our consciousness. Psychological experiences are valid only as they present themselves in self-observation; anything we add or derive through abstraction in the formation of concepts is an illusory apparition, a mere fabrication of the intellect, which can never be represented in our consciousness and thus lacks objective reality. Therefore, for Berkeley, the immediate experiences of consciousness constitute reality, leading to a complete transformation in the relationship between being and appearance compared to what we find in objective materialism and objective idealism. While for the latter, true being exists as a conceptual framework that shifts within our subjective representations into mere phenomena, for Berkeley, true being consists solely of these representations, and concepts are empty fictions of the intellect: only individual representations exist in consciousness. This denial of the reality of concepts primarily targets materialism and its notion of matter, since the content of the latter is not presented in experience; it also challenges objective idealism, as the latter recognizes the knowledge of being as knowledge through concepts. In this negation of the epistemic significance of concepts, subjective idealism stands in stark opposition to Platonism. Such opposition, while maintaining the idealist principle, was possible only because the notion of the soul underwent a transformation in the development of philosophical thought, as noted in Leibniz's system. The measure of reality is no longer thought operating within concepts, as was the case in ancient philosophy; instead, it is now considered the immediate content of psychological life in general. Thus, Leibniz regarded representation and striving as properties of the real monads. From this perspective, where the content of the world is conceived in analogy to the immediate content of our own spiritual life, subjective idealism represents the most consistent realization of the idealist direction, while Leibniz's system occupies an intermediary position between the ancient form of idealism, which is entirely based on deductive reasoning through concepts, and the new idealism, which acknowledges the immediate content of psychological life.

Subjective idealism recognizes the immediate content of psychological experience as the only true reality, fully explaining why, in contrast to objective idealism, it adheres to an empirical theory of knowledge. However, to reach a metaphysical understanding of the world, it cannot entirely pursue an empirical standpoint nor completely renounce knowledge through concepts. Alongside the fictions of philosophy and the natural sciences, which derive from concepts, Berkeley must also admit a second form of illusory knowledge: dreams and illusions that evoke representations, which, based on thorough investigation and chiefly the testimonies of others, cannot be ascribed any validity. Since alongside illusory concepts there exist illusory representations, and since these can be completely analogous in content to other psychological experiences, determining whether representations possess true reality cannot rely on our immediate subjective experience, as it can when examining concepts; instead, it is necessary to compare them with the representations of others. The agreement of our subjective experiences with those of other people compels us to accept a shared spiritual existence with them. Thus, for Berkeley, the reality of things is presented in representations, while the criterion for the reality of these representations is found in their concordance among different beings. This commonality of representations simultaneously proves, according to Berkeley, the existence of a collective spiritual being, which, uniting all thinking entities, can only be conceived as a spiritual entity. Consequently, God, as the Intellectus infinitus, represents the true reality of things. Therefore, just as objective idealism inevitably leads to an individualistic philosophical system, subjective idealism culminates in a universal and pantheistic perspective.

This conclusion is unavoidable. As the objective characterization of the concept of the soul necessarily implies the existence of multiple souls, so too does the subjective characterization of being, while maintaining a distinction between merely subjective and universally significant knowledge, inevitably lead to projecting the subjective into an infinite consciousness, or, in other words, to understanding individual consciousness as an emanation from the infinite intellect. These conclusions clearly demonstrate that a theory of knowledge based solely on subjective experience must again resort to the operations with concepts that it has rejected if it wishes to become a metaphysical worldview. If the Intellectus infinitus is conceived solely on the basis of the actual agreement of ideas among many individuals, it is, in any case, accepted as a common cause of the concordance of representations among various people. Such a cause cannot itself be a representation or immediate experience; it is a concept introduced through rational considerations. Since in Berkeley's view individual spirits and their representations transform into emanations from the divine spirit, his idealism represents yet again a metamorphosis of Christian idealism: among the new forms of idealism, it most vividly reflects the influence of Augustine's idea of the creation of souls and Neoplatonic notions of emanation; it closely resembles the form of Christian idealism articulated by Leibniz in the theological depiction of his system, particularly in his description of the relationship between God and the world.

In the eighteenth century, both forms of the new idealism, both objective and subjective, recede into the background: the objective transitions in Wolff's system into dualistic realism, which, in its general metaphysical assumptions, essentially represents a renewed Cartesian dualism; the subjective form in David Hume's doctrine evolves into critical empiricism, which fundamentally denies all metaphysics. From both currents and under their joint influence, Kantian transcendental idealism emerges as the conclusion of this period and the beginning of a new one. It serves as a metaphysical addition to Kant's critical theory of knowledge while significantly influencing the foundational tenets of transcendental idealism on the critical theory of knowledge.