A VITAL SCIENCE1 -Jack R. Holt A DISCUSSION Throw theory into the fire; it only spoils life. -Mikhail Bakunin, 1842 Some years ago I was asked to lead a faculty discussion about a book dealing with a biological subject. Silly me. I thought that the exchange would be fairly cursory, and that I would end up answering questions about biology. Instead, after an initial discussion and explanation of terms, several who objected to the book and its message because it was reductionist assailed me. This response took me by surprise because I had heard about this view and studied it in a course on the History of Science. I was intrigued to hear such anachronisms. I would have assumed that the whole exchange was tongue-in-cheek, except that the vocal participants were so passionate. Then, one of them (who retired from the university not long afterwards) in a patronizing tone advised me that I would never understand the real mystery of life until I adopted a more holistic view and rejected the notion that biology could be reduced to chemistry and physics. The theory that my antagonist defended was called vitalism. Since the time of Aristotle, it was believed that life and non-life were fundamentally different. They were so different that Georg Ernst Stahl (1660-1734) declared that living things were not governed by physical laws but by laws or principles that are unique to life and the products of life. Adding heat could destroy the vital force. For example, a living branch of a tree could have its vital force removed by burning and its products (carbon dioxide, water, etc.) rendered non-living. This separation is still apparent in the division of Organic and Inorganic Chemistry. The concept of vitalism persisted in the science of biology and medicine well into the 19th century. WHEN IS IT SCIENCE? All this made me feel that, to everyone of the main problems, I had better answers – more coherent answers - than they had. -Karl Popper Philosopher of Science Sir Karl Popper (1902-1994; see Figure 1) struggled with the question of science and what separates science from pseudoscience. He recognized that pseudoscience could sometimes be right and that science could be in error. What makes theory scientific? He cast about for a measure and found it in the way in which the theory was presented and explained phenomena. In particular, Popper rejected the idea that scientific theories could be proven or even verified. He said what makes a theory scientifically valid is that it can be shown false or falsified. This, he thought was the fundamental attribute of science and that which separated science from pseudoscience. Consider the rival theories of vitalism and mechanism in the 18th century and evaluate them them with Popper’s falsification requirement. The Mechanist theory was a view that there was no fundamental difference between life and non-life and that all of nature existed on a continuum from inorganic to organic. A prediction of the mechanists was 1 This is a revision of an essay that I wrote in 1998 and published in a collection called Paths of Science in 2001. 1 that spontaneous generation of life should occur often. The microscope had been invented and very tiny things were observed in drops of water and scrapings from teeth. Surely, things as simple as these could appear spontaneously. We all see this spontaneous generation as bread goes moldy and forgotten soup in the refrigerator turns cloudy and begins to stink as it teems with bacteria. FIGURE 1. Sir Karl Popper The Vitalist prediction was that the mold and microbes appeared only because they came from spores that fell from the air or were not killed by the boiling. That is, spontaneous generation was not possible. Experiments had been performed in which beef or mutton broth were boiled and then sealed. John Needham (1713-1781) performed the first such experiment or test of the Vitalist theory. He boiled meat broth, sealed it, and the sealed broth began to turn cloudy. He used this as a confirmation of spontaneous generation. An Italian named Lazarro Spallanzani (1729-1799) objected and said that Needham did not boil the broth long enough. Spallanzani repeated the experiment but boiled the broth for nearly 2 hours before he sealed the flasks. This time, the broth did not become cloudy. Mechanists like Needham said that Spallanzani boiled the flask so long that he destroyed the vital principle in the air and so spontaneous generation could not occur. Needham’s objection seemed almost vitalistic. In Popper’s view, the Mechanist theory could be scientific, but its proponents did not set clear boundaries to demonstrate that they were false. The theory seemed to be true regardless of the outcomes. So, it failed Popper’s most important test. All scientific theories must be falsifiable. NORMAL OR REVOLUTIONARY? A scientific theory is usually felt to be better than its predecessors not only in the sense that it is a better instrument for discovering and solving puzzles but also because it is somehow a better representation of what nature is really like. -Thomas S. Kuhn (1970) In a mild rebuttal to this idea, another philosopher of science named Thomas Kuhn (1922-1996; see Figure 2) said that scientists work to confirm their theories, not to disprove them. In fact it runs counter to human nature to expect otherwise. He describes normal science as an activity of puzzle-solving. In this, scientists accumulate data and 2 information as it is important within the context of a major theory or paradigm. Vitalism is an example of such a paradigm. FIGURE 2. Thomas S. Kuhn Sometimes, in the period of normal science, rival paradigms will arise (as in our example of mechanism vs. vitalism). Scientists then choose the paradigm that helps to better explain the phenomena explored by the theory. Scientists like Einstein, Newton, Darwin, and Mendel were revolutionaries. The hundreds of contemporary scientists who worked in the normal science mode as puzzle-solvers are much less well known. Revolutionaries make a better story. As in political revolutions, scientific revolutionaries sometimes end as intellectual martyrs. Such was the case of Ignaz Semmelweis (1818-1865; see Figure 3), a Hungarian born physician who came to the hospital of Vienna as a trainee in the obstetrics ward from 1844-1848. The hospital had two different birthing wards. The First Maternity Ward was staffed by physicians and the Second Ward by midwives. That said, he was disturbed by the disparity in death rate between the two wards. Women in The First Ward suffered a death rate of 6.8-11.2% due to an infection called Childbed Fever. The Second Ward had a death rate of only 2-2.5% in the same period. It seemed to Semmelweis that the cause for this could be found and treated. Also, he was certain that the problem represented a difference in the two wards. So, he set about trying a long list of tests. He tried having women deliver on their sides. He changed the route that the priest walked as he went to give last rites to a dying patient (in case the presence of the priest scared the women to death). He was nearly ready to give up when he went to Venice for a vacation to clear his head and attempt to think through the problem. Upon his return to Venice, he learned that the head of Forensic Surgery named Kolletschka had died of all the symptoms of Childbed Fever. This had come on him after he cut himself with a knife during an autopsy. Semmelweis reasoned that Kolletschka had introduced cadaverous (dead) tissue into his bloodstream thereby transmitting the disease to him. Similarly, women in the First Ward were attended to by medical interns who had spent the morning dissecting cadavers. If they carried any "cadaverous" material on their hands or under fingernails, they could transmit the disease to women who had given birth. In 1847, Ignaz Semmelweis instituted a policy of thoroughly washing hands before seeing patients in the First Ward. Quickly, the death rate dropped from more than 12% to less than 2% in the same year. 3 FIGURE 3. Ignaz Semmelweis Semmelweis had pursued a puzzle and solved it. Indeed, he seemed almost revolutionary. However, the physicians were not impressed. By 1848 he was expelled from the hospital, and he finally ended his days in an Insane Assylum where he died. The cause of his death was somewhat mysterious and he may have been the victim of murder. Why didn’t medicine follow his lead? Mainly because the "theory" of Semmelweis did not explain anything. He made certain changes and the death rate dropped. What was the connection? How could the transmission of cadaverous material cause disease? GERM THEORY An investigator with the standard medical view in mind, let alone one with a brain swept clean of all pre-hypotheses, could never have developed the whole concept of infecting microbes from the small evidence with which Pasteur began. -David Bodanis (1988) Louis Pasteur (1822-1895; see Figure 4) had an undistinguished career as a student and received his Ph.D. in Chemistry in 1847, the same year as Semmelweis’ discovery. He had a short temper with a somewhat arrogant air about him. Still, he was a genius at cranking out ideas. Through the 1850’s he began to work on fermentation. Also, during this time he finally laid to rest the concept of spontaneous generation by a set of brilliantly conceived demonstrations that built on the work of Spallanzani.