Gustav Fechner was born April 1, 1801.  His father, a village pastor, died early in Gustav’s childhood, so he, with his mother and brother, went to live with their uncle.  In 1817, at the age of 16, he went off to study medicine at the University of Leipzig (were Weber was teaching).  He received his MD degree in 1822 at the age of 21.

But his interests moved to physics and math, so he made his living tutoring, translating, and occasionally lecturing.  After writing a significant paper on electricity in 1831, he was invited to become a professor of physics at Leipzig.  There, he became friends with a number of people, including Wilhelm Wundt, and his interests moved again, this time to psychology, especially vision.

In 1840, he had a nervous breakdown, and he had to resign his position due to severe depression.  At his worst, he stayed in his rooms alone, avoiding light which hurt his eyes, and even painted his room black.  While lying in bed one morning, October 22, 1850, he suddenly realized that it was indeed possible to connect the measurable physical world with the mental world, supposed to be inaccessible to scientific investigation!  As his condition improved, he returned to writing and performing endless experiments, using mostly himself as a subject.

Like many people at the time, he found Spinoza’s double-aspectism convincing and found in panpsychism something akin to a personal religion.  Using the pseudonym Dr. Mises, he wrote a number of satires about the medicine and philosophy of his day.  But he also used it to communicate, often in an amusing way, his spiritual perspective.  As a panpsychist, he believed that all of nature was alive and capable of awareness of one degree or another.  Even the planet earth itself, he believed, had a soul.  He called this the day-view, and opposed it to the night-view of materialism.

Further, he felt that our lives come in three stages -- the fetal life, the ordinary life, and the life after death.  When we die, our souls join with other souls as part of the supreme soul.

It was double-aspectism that led him to study (and name) psychophysics, which he defined as the study of the systematic relationships between physical events and mental events.  In 1860, he topped his career by publishing the Elements of Psychophysics.

In this book, he introduced a mathematical expression of Weber’s Law.  The expression looked like this...

*R /R  = k

which means that the proportion of the minimum change in stimulus detectable (*R) to the strength of the stimulus (R) is a constant (k). (R is for the German Reiz, meaning stimulus.)  Or...

S = k log R

where S is the experienced sensation.

Fechner died November 28, 1887.

What Weber and Fechner showed that makes them far more significant than just Weber’s Law is that psychological events are in fact tied to measurable physical events in a systematic way, which everyone had thought impossible.  Psychology could be a science after all!