The vital force theory was a philosophical, scientific and spiritual belief that organic material contained a "vital force" that enabled them to live. The resulting Vitalism Theory was first proposed in the 16th century and lasted until the mid-19th century.
The vital force theory, or vitalism, was based on the idea that every living thing had a soul or spirit. According to this theory, inorganic materials were devoid of life because they did not contain this vital force. In living organisms, the vital spirit was a substance that infused with the body of an organism to give life. Vitalism was developed during the 16th century as a contrast to the mechanistic view, which explained that animals and human beings are mechanical devices different from artificial devices only in their degree of complexity. French anatomist Xavier Bichat identified 21 distinct kinds of tissue in the body and managed to explain the behavior of organisms in terms of their "vital properties." Through his experiments, Bichat concluded that there were additional fundamental forces in nature that maintained the physical and chemical processes in the human body. By the end of the 19th century, vitalism was discredited as a logical theory because it made unfalsifiable claims with no definite predictions.