Charles Hartshorne (/ˈhɑːrtshɔːrn/; June 5, 1897 – October 9, 2000) was an American philosopher who concentrated primarily on the philosophy of religion and metaphysics, but also contributed to ornithology.

After resigning from the ministry in late 1927 or early 1928, within a few years Francis was appointed pension fund manager of the Protestant Episcopal Diocese of Philadelphia.

He then returned to Harvard University as a research fellow from 1925 to 1928, where he and Paul Weiss edited the Collected Papers of Charles Sanders Peirce v. 1–6 and spent a semester assisting Alfred North Whitehead.

[2] Hartshorne acknowledged that he was greatly influenced by Matthew Arnold (Literature and Dogma), Emerson's Essays, Charles Sanders Peirce, and especially by Alfred North Whitehead.

He also found inspiration in the works of Josiah Royce (Problem of Christianity), William James, Henri Bergson, Ralph Barton Perry and Nikolai Berdyaev.

He conducted a lengthy correspondence over some twenty-three years with Edgar S. Brightman of Boston University about their respective philosophical and theological views.

In turn Hartshorne has been a seminal influence on the theologians Matthew Fox, Daniel Day Williams, Norman Pittenger, Gregory A. Boyd, Schubert M. Ogden (born March 2, 1928) and John B. Cobb, on the American philosophers Frank Ebersole, Donald Viney and Daniel Dombrowski, and on the Australian biologist-futurologist Charles Birch.

Contemporary process philosophy arose in large measure from the work of Alfred North Whitehead, but with important contributions by William James, Charles Peirce, and Henri Bergson, while Hartshorne is identified as the seminal influence on process theology that emerged after World War Two.

The motif of empiricism in process thought refers to the theme that experience is the realm for defining meaning and verifying any theory of reality.

Unlike classical empiricism, process thought takes the category of feeling beyond just the human senses of perception.

Another difference between Whitehead and Hartshorne is that the Englishman usually spoke of God as a single actual entity whereas Hartshorne thought it better to think of God as a personally ordered series of actual entities, each exhibiting the abstract character of divinity, as necessarily supreme in love, knowledge and power.

While Hartshorne believed that his reformulated ontological argument is sound, he never claimed that it was sufficient unto itself to establish the existence of God.

Throughout his career, from the time of his dissertation, he relied upon a multiple argument strategy, commonly called a cumulative case, to establish the rationality of his di-polar theism.

In the economy of his argument Hartshorne has attempted to break a perceived stalemate in theology over the problem of evil and God's omnipotence.

Positive criticism has underscored that Hartshorne's emphasis on change and process and creativity has acted as a great corrective to static thinking about causal laws and determinism.

His emphasis on nature and human-divine relationships to the world has goaded reflective work on developing theologies about pollution, resource degradation and a philosophy of ecology.

Hartshorne has also been an important figure in upholding natural theology, and in offering an understanding of God as a personal, dynamic being.

Hartshorne is also appreciated for his philosophical interest in Buddhism, and in stimulating others in new approaches to inter-religious co-operation and dialogue.

In these theological networks Hartshorne's panentheist reinterpretation of God's nature has been deemed to be incompatible with Biblical revelation and the classic creedal formulations of the Trinity.

Critics such as Royce Gordon Gruenler (born January 10, 1930), Ronald Nash and Norman Geisler argue that Hartshorne does not offer a tripersonal view of the Trinity, and instead his interpretation of Christ (Christology) has some affinities with the early heresy of the Ebionites.

Others have indicated that Hartshorne failed to understand traditional Christian views about petitionary prayer and survival of the individual in the afterlife.