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From time to time, I get to hang out with a wild and crazy gang of fisheries biologists.  They speak a different language as they discuss subjects like turbidity,  effluent limitations, and Secchi depth.

When I first heard that last term, Secchi depth,  I had to look it up.  Secchi depth, sometimes called Secchi disk depth,  is a measure of water clarity.  It is determined by use of a device called a Secchi disk.

A Secchi disk is a circular plate divided into quarters painted alternately black and white. The disk is attached to a rope and lowered into the water until it is no longer visible. Secchi disk depth, then, is a measure of water clarity. Higher Secchi readings mean more rope was let out before the disk disappeared from sight and indicates clearer water. Lower readings indicate turbid or colored water. Clear water lets light penetrate more deeply into the lake than does murky water. This light allows photosynthesis to occur and oxygen to be produced. The rule of thumb is that light can penetrate to a depth of 1.7 times the Secchi disk depth.

Upon further investigation, I learned that the Secchi disk was  invented in 1865 by a Catholic priest, Father Pietro Angelo Secchi. Although it has been improved upon a number of times, Fr. Secchi’s basic design remains in place today.

My discovery of Father Secchi led to an interest in other Catholic scientists. And indeed, history provides many outstanding examples.  The  list is so long that I’ve pared it down to five exemplary individuals.

Father Gregor Mendel (1822-1884)

Gregor Mendel, baptized as Johann Mendel, is universally acknowledged to be the father of modern genetics. He was born in what is now the Czech Republic. His family was German. He began studying for the priesthood in 1843 at the Abbey of St Thomas, an Augustinian institution.  Before entering the abbey, Mendel had worked his family’s farm.  He also studied physics and philosophy at Brno (then the principal city of Moravia; now in the Czech Republic).

After eight years at the abbey, Mendel was sent to the University of Vienna for two years.  At Vienna, his physics professor was another renowned scientist, Christian  Doppler. When Mendel returned to the abbey, he became a professor of physics.

Father Gregor Mendel

Father Gregor Mendel

Mendel had also studied astronomy and meteorology.  Most of his surviving academic writing concerns meteorology. But Mendel is best known for his paper, Experiments in Plant Hybridization.

Mendel’s magnum opus was based on his study of variations in peas which had been planted at the abbey.  He also studied honeybees, with which he had been familiar since his childhood experience on the family farm. From his experiments, Mendel derived two Laws of Inheritance. The first, the Law of Segregation, states that each individual has a gene or genetic locus for individual traits such as hair color, eye color, etc.  Each parent also contributes a gene to the offspring. The gene that becomes dominant will control the nature of the trait.

The second law, the Law of Independent Assessment states that any particular gene is passed from parent to off-spring independently from another gene for a different trait.

Mendel’s work was not widely understood during his lifetime.  It wasn’t until the early part of the twentieth century that scientists embraced Mendel’s genetic theories.  Today, Fr. Mendel’s work is the basis from which all modern genetic science proceeds.

Father Jean Picard (1620-1682)

Fr. Picard was a Jesuit mathematician, astronomer, and hydrologist.  Born to a large family in La Fleche, France, he later attended the Jesuit College Royal Henry-le-Grand. In 1644, he moved to Paris, where he began assisting a math professor named Pierre Gassendi.  Together Picard and Gassendi observed numerous lunar eclipses.  After Gassendi’s death, Picard became Professor of Astronomy at College de France in Paris.

In 1761, Picard became the first person to nearly accurately measure the size of the earth.  His 17th century numbers were 99.56% of the modern figures.

Father Jean Picard

Picard communicated with other scientists of his era and made significant discoveries outside his main field of  astronomy.   Very little else is known about Fr. Picard’s life.

Ignaz Phillipe Semmelweis (1818-1865)

Semmelweis was not a cleric at all, but he was Roman Catholic. He was born in what is now Hungary to  a well-to-do family. He set off to the University of Vienna, intending to study law. somehow, he ended up in medicine. At age 30, he was made assistant to the director of one of two maternity clinics at Vienna General Hospital.  This first clinic was used for the training of medical students.  The second maternity clinic was staffed by midwives.

Semmelweis soon discovered an odd statistic: maternal mortality rates at the first clinic where the students trained had twice, sometimes three times the rate of the midwife-staffed second clinic.  The leading cause of maternal mortality was septicemia.
After eliminating all the variables he could, Semmelweis was left with the conclusion that the only significant difference between the two clinics was the staff. But why did the medical students, with superb academic training have a greater mortality rate than the midwives who had not the benefit of academic training?

The answer turned out to be rather simple: the medical students also trained with cadavers and the midwives had no contact with cadavers.  The medical students took no hygienic steps between cadavers and infant deliveries and often used the same instruments for both activities. When Semmelweis  realized this, he instituted a procedure requiring the students and staff at the first clinic to wash their hands with a chlorine based solution.  Within a month, the mortality rate at the first clinic dropped to parity with the midwife clinic.

Semmelweis had proven something the significance of which escaped even himself: that hand washing could prevent the transmission of germs between persons. He believed he had succeeded only in preventing “cadaver contamination.”

Even the simplest understanding of Semmelweis’ accomplishment drew scorn and ridicule in the scientific community. Semmelweis was forced out of his position and run out of Vienna.

Dr. Ignaz Semmelweis

Aggravated, outraged and bitter, Semmelweis began to speak out against his opponents. He wrote vicious screeds against them. His associates and family came to believe he was  insane and had him committed to an asylum.  He died there two weeks later.  Some sources say septicemia was the cause of his death.

Father Pietro Angelo Secchi (1818-1878)

We end where we began.   Father Secchi was primarily an astronomer.  He studied astrophysics. After training by the Jesuits in Rome, Father Secchi embarked on an academic career.  He taught in the United Kingdom and at Georgetown University in Washington, D.C.  When he returned  to Rome, Fr. Secchi was made the director of the Observatory of the College of Rome (now called the Pontifical Gregorian University).

Father Pietro Angelo Secchi

His work in astronomy was prodigious.  He discovered three comets, including one named for hm.  He created the first classification scheme for stars. He made precise maps of lunar craters and color drawing of the planet Mars. And he invented the Secchi disk for use in another field in which he was interested.

Faith and Reason

As said above, the list of Catholics, both clerical and lay, who have made substantial contribution to science is a long one. It includes Roger Bacon,  Galileo Galilei, Rene Descartes, Nicolas Copernicus, Louis Pasteur, Blaise Pascal, André-Marie Ampère, Enrico Fermat, and many more.

Some Catholics and non-Catholics question whether the Church can really exist successfully in  a  science-influenced world.  Aren’t faith and reason polar opposites? And by the way, what about that business with Galileo, whose publications were banned and who spent the latter portion of his life imprisoned or on house arrest for suspected heresy?

For what it’s worth, Galileo was effectively rehabilitated in the 18th century.  In the twentieth  century, Pope Pius XII called Galileo one of the “most audacious heroes of research.”  In 2008, the Church celebrated the 400th  anniversary of Galileo’s earliest telescopic observations.

The Catechism of the Catholic Church holds:

159      Faith and science: “Though faith is above reason, there can never be any real discrepancy between faith and reason. Since the same God who reveals mysteries and infuses faith has bestowed the light of reason on the human mind, God cannot deny himself, nor can truth ever contradict truth.”

“Consequently, methodical research in all branches of knowledge, provided it is carried out in a truly scientific manner and does not override moral laws, can never conflict with the faith, because the things of the world and the things of faith derive from the same God. The humble and persevering investigator of the secrets of nature is being led, as it were, by the hand of God in spite of himself, for it is God, the conserver of all things, who made them what they are.”