Mortimer Jerome Adler (/ˈædlər/; December 28, 1902 – June 28, 2001) was an American philosopher, educator, encyclopedist, popular author and lay theologian.

[1] While doing newspaper work and taking night classes during his adolescence, Adler encountered works of men he would come to call heroes: Plato, Aristotle, Thomas Aquinas, John Locke, John Stuart Mill, and others, who "were assailed as irrelevant by student activists in the 1960s and subjected to 'politically correct' attack in later decades.

[3] In Adler's view, these errors were introduced by Descartes on the continent and by Thomas Hobbes and David Hume in Britain, and were caused by a "culpable ignorance" about Aristotle by those who rejected the conclusions of dogmatic philosophy without acknowledging its sound classical premises.

These modern errors were compounded and perpetuated, according to Adler, by Kant and the idealists and existentialists on the one side, and by John Stuart Mill, Jeremy Bentham, and Bertrand Russell and the English analytic tradition on the other.

[6] Adler soon returned to school to take writing classes at night, where he discovered the western philosophical tradition.

After his early schooling and work, he went on to study at Columbia University and contributed to the student literary magazine, The Morningside, a poem "Choice" (in 1922 when Charles A. Wagner[7] was editor-in-chief and Whittaker Chambers an associate editor).

[15] After the Great Books seminar inspired Chicago businessman and university trustee Walter Paepcke to found the Aspen Institute, Adler taught philosophy to business executives there.

[10][16] Adler long strove to bring philosophy to the masses, and some of his works (such as How to Read a Book) became popular bestsellers.

[21] Many years later, he wrote that its "intellectual austerity, integrity, precision and brilliance ... put the study of theology highest among all of my philosophical interests.

He also greatly admired Henri Bergson, the French Jewish philosopher and Nobel laureate, whose books the Catholic church had indexed as prohibited.

In volume 51 of the Mars Hill Audio Journal (2001), Ken Myers includes his 1980 interview with Adler, conducted after How to Think About God was published.

"[24] Myers notes that Adler finally "surrendered to the Hound of Heaven" and "made a confession of faith and was baptized" as an Episcopalian in 1984, only a few years after that interview.

[25] In December 1999, in San Mateo, where he had moved to spend his last years, Adler was formally received into the Catholic Church by a long-time friend and admirer, Bishop Pierre DuMaine.

Adler was a self-proclaimed "moderate dualist" and viewed the positions of psychophysical dualism and materialistic monism to be opposite sides of two extremes.

Adler's study concluded that a delineation of three kinds of freedom – circumstantial, natural, and acquired – is necessary for clarity on the subject.

[32][33] As Adler's interest in religion and theology increased, he made references to the Bible and the need to test articles of faith for compatibility with the conclusions of the science of nature and of philosophers.

[2] Adler stressed that even with this conclusion, God's existence cannot be proven or demonstrated, but only established as true beyond a reasonable doubt.

Furthermore, there is no reason to be surprised when discussions such as those about the "death of God" – a concept drawn from Friedrich Nietzsche – stir popular excitement as they did in the recent past and could do so again today.