Thank you for your thoughtful questions. Philosophy, in this case, invites us to introduce greater clarity into the use of concepts.

a) Suffering can be understood in a very broad sense. The limits of cognition can be perceived as a source of suffering. For example, the fundamental inability of the human mind to provide a definitive answer about the existence of God (as once emphasized by Kant) may cause suffering. For Hegel, the process of cognition can be interpreted as a form of suffering: consciousness discovers that there are phenomena around it that are not fully knowable, and that consciousness itself is not fully transparent to itself. Later, the existentialists radicalized this problem by examining human relations: the presence of another “I” both limits my freedom and forces me to construct myself. This may lead to suffering, even to the realization (famously expressed by Sartre) that “others are hell.”

b) If we accept the position of metaphysical personalism, it is no longer possible to speak of matter as a substance independent of consciousness from which reality is constituted. In this respect, the philosophers of the Tartu personalist school were influenced by Leibniz and Lotze.

As continuers of the Platonist and rationalist tradition, they believed that the acquisition of new knowledge essentially means an increase in the intensity of consciousness: the subject discovers knowledge that is already initially given within itself. They therefore understood objective existence not as a world of sensibly perceptible things, but as a system of concepts in which all concepts are interconnected.

c) Metaphysical personalists were not solipsists. They acknowledged the existence of multiple centers of consciousness or substantial “I”-units which, through their interaction, generate sensations. However, this does not imply recognition of the real existence of matter as an independent substance. Rather, the issue can be interpreted in terms of several levels of semiotics. One form of semiotic cognition allows the subject to recognize other centers of consciousness, which are equally real but can be known only through “bodily signs” or sensations.

Thank you for this important and thought-provoking question.

First, it should be noted that personalism as a philosophical current is internally diverse and encompasses several distinct traditions. My focus is on the nineteenth-century Tartu School of Personalism.

Personalist thinkers within this tradition frequently polemicized against Darwinism and the natural sciences, particularly in discussions of the relationship between the body and consciousness. Their critique of materialism and dualistic models typically rests on two interconnected arguments.

a) The only reality directly given to us is consciousness.
b) The concept of “matter” is a metaphysical construct.

Whether we speak of the brain, the nervous system, or any physical organ, all such entities fall under the broader concept of the matter. But what is “matter”? According to Tartu personalists, it is not something immediately given; rather, it is a conceptual synthesis through which we designate multiple sensory perceptions. In other words, “matter” is an abstraction that is formed within consciousness.

The first Latvian philosopher, Jēkabs Osis, formulated this in his lecture notes:

"Speaking of matter, we think of sensations. The idea of matter is just an idea, and a metaphysical idea; based on the data that are within us, we judge what is outside us".

This raises a further question: what can unify diverse sensory perceptions and form abstract concepts? For the Tartu School, this is the substantial unity of the “I.” The substantial “I” serves as the foundation of personality and the ontological ground of reality. Because it is the condition for the formation of the concept of matter, it cannot itself be material or physical. The “I” produces the idea of matter within consciousness and subsequently projects or “transfers” it to external reality.

As a metaphysical form of personalism, the Tartu School emphasizes the ontological primacy of the substantial self. Without this substantial core, existence would be unintelligible. At the same time, personality characteristically externalizes the contents of its consciousness and may mistakenly assume that these objectified contents, such as “matter”, are ontologically more fundamental than the person. This gives rise to the impression that reality consists of matter.

Twentieth-century personalist movements, such as Emmanuel Mounier’s personalism, developed the tradition in a different direction. While retaining a focus on the dignity of the person, they emphasize existential and political dimensions and criticize attempts to define the individual primarily through collective identities such as class, nation, or state.