experiencing evolution 211rian ministry. But the first of numerous bouts of ill health, physical and mental,
led to a postponement of his seminary studies, while he spent a few years as
a subassistant on the Geological Survey of Pennsylvania, headed by Henry
Darwin Rogers. Hoping to become a missionary to rural Pennsylvania, he
attended Princeton Theological Seminary for three years, then spent some time
in Europe, exposing himself to German rationalism and higher criticism of
the Bible. He returned with his faith pretty much intact and began working as
a colporteur among the poor German settlers in the hills of Pennsylvania.^19
The strenuous labor undermined his health, and after two years he re-
joined the geological survey. By 1848, having received a ministerial license
from the Presbytery of Philadelphia, he was pastoring a Congregational church
in Milton, Massachusetts, near Boston, where he came under the influence of
Unitarians, including his wife-to-be, Susan Lyman. Under circumstances that
remain vague, the Presbytery charged him with harboring “infidel” sentiments
and “denying the Inspiration of the Scriptures.” He adamantly denied being
an infidel, but confessed to putting the truths of science above the teaching of
the church. In May 1849, the Presbytery withdrew his license to preach. His
“theological troubles” literally split the church and exacerbated his poor health.
In 1851, he left the ministry yet again and returned to the geological survey.
However, his behavior was so erratic and his temper so terrible that Rogers
fired him, fearing that “insanity is evidently growing upon him.”^20 For years
thereafter Lesley struggled to earn a living, working variously as a coal expert
for the Pennsylvania Railroad, as secretary of the American Iron Association,
and as librarian of the American Philosophical Society.^21
Shortly after the end of the Civil War, Lesley returned to Boston to deliver
the prestigious Lowell Lectures, on “Man’s Origin and Destiny, Sketched from
the Platform of the Sciences.” His liberal wife, perhaps sensing the manic
mood of her husband, urged him not to offend his audience by unduly criti-
cizing religion. Though he prided himself on always speaking the truth, he
assured her that he had trimmed his language and made his “statements of the
oppositions of Science and Religion as mild as possible.” Despite his promise, he
began his lectures sounding like an American Huxley or Tyndall, arguing that
“Jewish Theology and Modern Science...areirreconcilable enemies” and that
Genesis is “a poem, not a text-book.” He dismissed theology as “science falsely
so called” and blamed the “unchristian state of the theological and social sci-
ences” for retarding the progress of science.^22
Hearing such rhetoric, his auditors might have anticipated an early en-
dorsement of Darwin’s new theory. But no. Lesley professed to accept organic
evolution only “if keptwithin the regions of variety.” Before admitting more
extensive evolution—of genus, family, or class—he wanted to observe “nature
in the very act of exchanging one species for another.” Even then he was con-
fident that the evidence would show not one but four lines of evolutionary
development, each corresponding to one of Georges Cuvier’s divisions of the