Immortal Passage: Philosophical Speculations on Posthuman Evolution is Asher Seidel's speculative account of posthuman evolution. Seidel begins with the transitional period in which humans begin to live for significantly extended periods, then moves to the closer future in which, having transitioned, the now posthumans enjoy enhanced cognitive and creative powers. Finally, Seidel enters the distant future, where our descendants might possess abilities beyond the limits of what is presently conceivable. Seidel's speculations engage various philosophical problems. Seidel seeks an ethical theory that co-develops with a deeper scientific understanding of ourselves. He also examines the metaphysical and epistemological presuppositions of his recommendation for human to posthuman transitioning, including mind-body dualism vigorous enough to allow for full-bodied consciousness, but insufficient for freewill; perceptual direct realism; and self-identity. As the speculations reach further into the future, various socio-political questions regarding the difficulties of transitioning are explored. Speculated possibilities of pain-free living, cooperative relationships, nonbiological selfhood, and radically enhanced cognitive abilities, are examined in depth in this mind-bending ride into the future of humankind.

Inhuman Thoughts is a philosophical exploration of the possibility of increasing the physiological and psychological capacities of humans to the point that they are no longer biologically, psychologically, or socially human. The movement is from the human through the trans-human, to the post-human. The tone is optimistic; Seidel argues that such an evolution would be of positive value on the whole. Seidel's initial argument supports the need for a comprehensive ethical theory, the success of which would parallel that of a large-scale scientific revolution, such as Newtonian mechanics. He elaborates the movement from the improved-but-still-human to the post-human, and philosophically examines speculated examples of post-human forms of life, including indefinitely extended life-span, parallel consciousness, altered perception, a-sociality, and a-sexuality. Inhuman Thoughts is directed at those interested in philosophical questions on human nature and the best life given the possibilities of that nature. Seidel's overall argument is that the most satisfactory answer to the latter question involves a transcendence of the present confines of human nature.

Inhuman Thoughts is a philosophical exploration of the possibility of increasing the physiological and psychological capacities of humans to the point that they are no longer biologically, psychologically, or socially human. The movement is from the human through the trans-human, to the post-human. The tone is optimistic; Seidel argues that such an evolution would be of positive value on the whole. Seidel's initial argument supports the need for a comprehensive ethical theory, the success of which would parallel that of a large-scale scientific revolution, such as Newtonian mechanics. He elaborates the movement from the improved-but-still-human to the post-human, and philosophically examines speculated examples of post-human forms of life, including indefinitely extended life-span, parallel consciousness, altered perception, a-sociality, and a-sexuality. Inhuman Thoughts is directed at those interested in philosophical questions on human nature and the best life given the possibilities of that nature. Seidel's overall argument is that the most satisfactory answer to the latter question involves a transcendence of the present confines of human nature.