This paper is devoted to the philosophical analysis of the problem of loneliness in the contemporary social reality. The topicality of the problem of loneliness is the result of the specificity of the contemporary social reality state. The characteristic features of this reality are: the processes of informatization, the change of the world picture, the estrangement, the transformation of person's identity, the deficiency of inter-personal connections and the chaotic state of the social space. These phenomena lead to irreversible changes of the inner world of a person, when loneliness becomes an invariable companion and gains special features due to the new reality. In these social conditions a person experiences and realizes loneliness as a result of incommensurability of the inner I and the outer manifestation of I for the Other One. In the paper the phenomenon of loneliness will be interpreted through the prism of the person's search of identity and the co-occurring process of estrangement. The basic thesis of this paper includes the following: the dynamic change of social life entailed the transformation of the person's identity. The difference of I as the unique and different creature from the Other One is formed in the process of selfdetermination. Interrelations with "the world of Other Ones" give situations of mutual conflicts and estrangement, which, in turn, cause loneliness. Loneliness, investigated philosophically, manifests itself as a special way of person's existence and is an immanent state of one's consciousness, constituting the limits of personal existence as dissociating oneself and realizing one's own autonomy. A person existing in a society is subjected to estrangement. The process of life communications assumes interaction of I with the "world of the Other Ones". Interrelations with the Other Ones have a dual character. The Other Ones are important and necessary for I, as they are the source of knowledge about me as a unique human being. They are also the source of my own negative senses, a secret threat for my existence. Interrelations with the Other One are connected with the expectation of a reaction to my actions. Possible situations of interaction of I with the "world of the Other Ones" cause the following forms of estrangement, which are the basis of specific features of loneliness: social, communicative, self-estrangement, cultural and moral estrangement. All these forms of estrangement lead to various dimensions of loneliness. The specific feature of the philosophical approach to the problem of loneliness allows to show the ambivalent nature of the given phenomenon and to show that loneliness in the contemporary world becomes an unavoidable, immanent inherent way of person's existence.
