Life, more than Physics and Chemistry? Lead: Philip Fernadez & Melissa Russell

4/10/2007

Summary by Evan Jordan

Life, more than Physics and Chemistry?

The topic of the nights interest posed the question; “ What is life: can physics and chemistry explain everything?” This interesting thought typically leads one to the conclusion, ‘yes,’ but what is consciousness and what is this mind of ours? The presenters of the topic, one from a physics and the other from a chemical engineering background, made it clear that from a scientific standpoint, yes, they believe physics and chemistry can explain the components of life.

First, they accurately described life as: Life systems are organized, self-constructing, replicating entities that are capable of transducing energy (transducing is turning energy from one form to another). Nucleic acids are the blueprints with which proteins collaborate to produce the growth and life cycle of a living organism. The presenters found it interesting that life changes energy although they were not able to describe it. They titled nucleic acids as the matter that is responsible for this indirectly, directly through proteins. They then proposed the question, “Do you think this is what life is?”
Everybody thought that this was a relatively good description of life, but does this definition explain what life is or does it help to explain what does not have life. Overall it was found that life is not easy to define because of different problems that exist. Some examples were brought to our attention by Dr. Davis and a few audience members. Mules for example, are a hybrid between a horse and a donkey but are not able to reproduce. Since they are not able to reproduce are they no longer considered living entities? All of us seemed to agree the mules are living, so if the offered definition of life were taken too seriously, then we could find specific examples that would describe many living organisms as non-living. Prions and viruses were also brought to our attention. Dr. Davis recounted reasons why these are generally not considered to be life but stated that this type of discussion will get us to a dead end: defining life is not easy. Prions are proteins that cause aberrant changes in other proteins causing them to function improperly. Viruses need a metabolizing cell to exist and they do not have a functioning metabolism. But it was pointed out that Homo sapiens need the earth or earth-like environment to live in; hence we are like viruses of the earth. Mutualism or parasitism is the question.

The presenters then made it clear that throughout history, the definition of life tends to be hard to explain when encompassing all living beings especially when organisms are smaller and simpler. Aristotle considers living things to be composed of specific types of matter, or things composed of particular elements. This is a rather broad definition but it would hold true for living things, non-living things, unexplainable things, and so on. Dr deVries elaborated a little more on Aristotle. Aristotle thinks that there are smooth variations between non-living things, plants, to animals to humans. Plants have vegetative souls whereas animals add to that with a perceptive soul. Some entities allow the food to come to them whereas animals seek food through mobility and perception. On top of that, humans have a rational soul; we are able to recognize absolute truths. Again he states there is a smooth transition from beings like animals, which are more capable of movement/perception to others with fewer capabilities.

Descartes was another person who elaborated on this idea. His ideas focused on mind and matter. DeVries explains how Descartes was a physiologist as well as a philosopher, so Descartes had several disciplines to draw on while considering the question, “What is life?” He considered organisms to be very complex machines like automatons. An automaton is a cleverly created, life-like machine that can do complex actions in the world. Descartes would say a squirrel getting around a protective disc to get to the birdfeeder is an example of an automaton. He believes that only humans have souls and that there is not much more to life than physics and chemistry. When explaining the mind Descartes has problems and refers to God as creator of mind substance and body substance. He believes that they neither come into or out of existence. Minds continue to persist without their respective bodies, but they are not able to perceive in the ways they could do with a body. They exist this way because they are always thinking, even though not necessarily continuous, a thought that the class was ambiguous about. You could not have a mind that does not think, just as you could not have a body that does not take up space.

One member of the audience ties thinking to physics, because we know that when you are thinking, electrical impulses are being generated in the brain. Also the electrical impulse is generated in some unit of time; therefore you must have a break from thinking all the time. But this idea was not known to the past people. Also the brain is not completely understood, so this direction of discussion would lead to an unfinished one, since the truths of the brain are not completely understood.

Subconscious thought was brought to everybody’s attention as a possible way to always be thinking. Again the knowledge in this area is limited, although Descartes described it as thinking that could not be brought to our attention, he also has trouble explaining this phenomenon. He simply stated that what separates us from animals is our mind.

Descartes believed that there are two ways one can detect mind. A body alone would not be capable of complex language, because language has an infinite diversity. Also it is not possible to build a rational automaton (at least in this day and age, or in Descarte’s) that could respond to all the situations that peoples are exposed to.

Again back to the mind and body essence. Descartes believes in a God that has does everything. In Descarte’s conception, God creates bodies out of one substance and minds out of another substance. And if you wanted to find this mind substance then you would be wasting your time if you dabbled into physics and chemistry. Mind substance is like a pool of water, you are given a glass and I am given a glass, they are different parts of the water but made of the same material. This is a metaphor trying to explain why one mind is different from another (no connection to Descartes).

A new topic was brought to us by the presenters. The vitalist vs. the mechanist. Vitalists believed that the functions of a living organism were the product of psycho-chemical patterns. They searched for the life force. Mechanists, on the other hand, believe that everything can be reduced to a matter of physics and chemistry. For those intrigued by vitalism, a movie called “20 grams”, the title of which is about weighing dead people to see if they weighed less than when they were alive. For the mechanist, a joke was brought to our attention; A climber finds a high plateau, he finds a shepherd and asks if he can have a chunk of cheese. The shepherd has none to spare, the climber proposes that if he can guess the number of animals in the flock exactly then he is rewarded a chunk of cheese. The shepherd agrees and the climber guesses the exact number, 328 sheep. The shepherd is amazed and gives him some cheese. But then the shepherd proposes another bet: 100 Swiss francs that he can guess the climber’s profession. They agree and the shepherd guesses right. How did he know that the climber was a molecular biologist? Because the animals were goats not sheep.

This raised a discussion on reductionism vs. holism. Points were made for both sides and it was concluded that you need a portion of both to have a good understanding of what’s going on. Dr. Davis on the other hand raised an interesting point against the reductionism. Sometimes breaking things to pieces will not provide answers. Say you saw a joke on television and you want to know why it was funny. You can break apart the machine and find no answers. The TV is only a medium for which the answer lies elsewhere.

Well the question was, then, do we know how memories are stored? Dr. deVries clearly stated no, but that it must indeed be body or mind orientated. There are no traces of memories that we know of, although there are memory traces of some kind but we do not know what they are or where they might be. The presenter then stated that it is the same idea that Descartes was stuck on, we know nothing about the mind substance.

So the discussion then focused away from the mind. A reaction of chemicals was posted on the board which led from product A to product B. But in between there were many steps that occurred along the way which were observable as a function of time. But how can we account for all the different chemical formations if for instance they occur during a minute time quantity or they are simply not observable? The discussion then led to the human invention of models. They are typically created to help remember something or to explain a complex idea to another individual. From this idea, the presenters presented another question,” Can we have a definition of life, can it be broken down?”

The discussion that ensued again boiled down to simpler/smaller organisms that seem difficult to define as life such as viruses. An arbitrary line was brought to our attention but even then the definition could not be clear cut, there would be too many exceptions within the definition.

While talking of life and some of its processes yet another problem comes about. What is the origin of life? Dr. Davis explained how the vitalists believed there is some principle to being alive. How did the initial interaction between DNA and proteins begin, because they both rely on each other for replication/synthesis? This is very similar to the chicken and egg problem and has yet to be solved. Scientists have tried to replicate the origins of life but have only generated amino acids out of spontaneous events that they believe represented the environment of early earth.

Moving on, the presenters then explained how life creates order out of disorder in order to survive. This in turn creates more entropy in the universe because life’s creation of local order inevitably increases universal disorder: this is a law in physics. It was established that when the body dies, it can no longer create order, and in turn will eventually reach thermo-dynamic equilibrium.

In conclusion, no universally agreed upon line had been defined between life and non-life. With so many exceptions it is rather pointless to write out this definition. And why we need this definition is still unknown to me. Physics and chemistry can explain most processes of the body but does not explain everything there is to the mind. Mating behavior can be attributed to both mind and body, and physics and chemistry will have a hard time defining that.