The philosophy of dementia
Professor of Neurology, School of Medicine, University of Thessaloniki

Throwing light on the fundamental nature of mind and understanding mental faculties such as cognition, learning and memory, from the philosophical viewpoint, apart from a mechanistic functionalism, became the main subject of the philosophy of the neurosciences or neurophilosophy. It is reasonable that in the spectrum of neurophilosophy dementias attract strongly the attention of scientifically-minded philosophers, who search for a cell-biological explanation of decline of cognition, which may be based on the substantial synaptic alteration at the pre- and postsynaptic level, the defective mechanisms of long term potentiation (LTP) and the eventual loss of the majority of the synapses at the cortex of the cerebral hemispheres and the subcortical centers, which are involved in information-bearing and memory processing. Although the morphological and functional alterations of the dendritic spines may interpret the phenomenology of the dementia and throw some light in the drama of the cognitive decline of the patients who suffer from dementia, however they can not give a reasonable and philosophically acceptable answer in the fundamental problem of the condition of the self in dementia. Is the self independent of the mental condition of the person or the self depends on the idea of the enduring self? It is obvious that the memory loss in dementia and the spatial-temporal alterations detach the self from the past and isolate it in the limited time of the present, without further perspectives for the future. However, we do not know the dimensions of the interior aspect of time, the subjective or personal time in patients who suffer from dementia, which may play an important role in the sense of duration and integration of the self. On the other hand, neuropsychological evidence demonstrates that demented persons, lacking access to autobiographic and episodic memory, can preserve the personality knowledge and retain their personal identity, which may be available and still functional in lack of memory. Personal identity may be based on subjective concept of the body, as well as on the memories and the character of the interior life. An important issue in dementia is the quality of the interior life and the moral principles of the amnesiac person. It is well known that the interior life is mostly understandable by the verbal, artistic and social behaviour and the interactions of the individual with the social environment. Therefore, the criteria of the interior life are based on the phenomena and not on the existential dimensions and the existential substrate of the self. The person, who is not submerged in the mass is able to cultivate virtues and aims even in a condition of memory impairment. Nevertheless, the depression in the initial stages of the dementia may reflect the grief for the ongoing dysfunction, the loss of perspectives and the lack of the capacity for self-organization and the increasing impairment of cognition. The insight of the mental tragedy in dementia is an evidence of an active interior life, even in the advanced stages of the disease. At the same time, the concept of the good and evil as well as the dignity of the individual are unaffected evidently by the loss of memory and the impairment of learning. The moral aspect of the life is in the majority of the cases unchanged by the decline of the mental faculties. As a rule, neuroscientists endeavour to approach the philosophy of dementia with the scepticism of the critical philosophy, which excludes speculation, emphasizing the importance of the clinical manifestations in space and time and the neuropathological data from the estimation of the morphological and morphometric alterations of the brain. We have the feeling that a phenomenological approach of dementia is not sufficient for a deeper understanding of the self in dementia. In contrast, a detailed analysis of the interior life and the existential dimensions of the individual would be required in order assess the continuation of the self and the integrity of the Being during the decline course of dementia. Encephalos 2010, 47(3):109-130.

Key words: Dementia, philosophy, Being, neurosciences, phenomenology.