Fundamental research in the present study considers the conscious mind and the world as co constitutive, inseparable components of the cognitive system, both on the empirical level accessible to positive science, and on the transcendental level revealed by philosophical analyses. It was motivated, on the one hand, by objections addressed to cognitive science that it neglected the cognitive role of consciousness and the environment by conceiving the mind as a multiply realizable computational-representational system and, on the other hand, by phenomenological descriptions of the unified structure of our world-conscious life and our being-in-the-world, after implementing the transcendental and ontological reductions respectively, which lack empirical verification. Following comparative analyses of different approaches in cognitive science, executed in the first, second and third part of the dissertation, further conceptual investigation is pursued according to the definition of cognition as the ability of living beings to cope with the world, which results in new but is conditioned by previous knowledge and skills. In other words, knowledge and skills are developed through constant interaction between an organism and its environment, and then applied to new situations. This interaction consists of different but interrelated processes of metabolism, homeostasis, reproduction, social behavior, autonomous action, bilateral adaptation, and making sense of the world. Presented research, therefore, supports the hypothesis that thinking is not only information processing based on a series of formal rules and performed in a sequence of steps according to given algorithms, nor is it just the recognition of patterns in the propagation of signals in a neural network, but a selective, regulative, intentional, embodied and situated activity of autonomous and social beings, aimed at achieving goals, self-preservation and adaptation. Before introducing the layered structure of the world into the thematic field of cognitive science, which is, according to the author, the original contribution of phenomenology, it was necessary to point out various aspects of consciousness having cognitive significance in the integration of information and global sharing of the results of modular processing, in coping with unfamiliar situations, consolidation of memory, imagining and planning, self-evidencing, establishing favorable environmental conditions, controlling purposeful behavior, reacting to selected stimuli, interpreting causal links, and immersing oneself in the mental states of others. The world, on the other hand, primarily as a natural and social environment, together with a hereditary genetic program, forms the capacities of a cognitive agent, determining how and what he will experience, how it will affect his behavior and, in turn, how will his actions change the conditions in that environment. However, phenomenological analyzes have revealed that the world as a universal spatio-temporal horizon, a background which defines objectivity, a permanent doxic basis, a dynamics of the known and the foreign, of the present and the absent, a network of significance, a motivational system and an intersubjectively formed reality, is not something external to the conscious mind. Life is a multilevel correlation of the subject and the world, forming the correlates as two opposing poles but parts of the same dynamic process. The transcendental level of the correlation is revealed in the present study through eidetic descriptions of phenomena that underlie this two-sided conditioning, namely constitutive intentionality, embodiment, intersubjectivity and historicity. Temporality, which manifests as cognitive, organic, objective and ecstatic-differentiating time, is now seen as the primal phenomenon or connective tissue that holds the transcendental sphere together. In conclusion, scientific and philosophical arguments in this interdisciplinary research confirm that objectively valuable knowledge that can be obtained, articulated, developed and transferred, arises from the dynamic interaction of conscious, embodied subject and its complex and changing natural, social and cultural environment, thus indicating the inadequacy of the traditional paradigm of the mind as a computer as well as contemporary neurocentrism in cognitive science.