Cosmology and our View of the World
The Questions of Life
Lead: Thomas Davis
Summary by Clifford Laney
The Questions of Life
When discussing the relation of the science of the universe to our spiritual perspectives, one topic has a very significant relevance: Life. There are several important topics relating to life in the universe. Biology seeks an understanding of this topic because it is central to the development of a science of life. The origin of life is one of the most controversial and important questions in defining and understanding life. Why is there life in the Universe? Is earth the only planet sufficient for life, or is there life elsewhere in the universe? How does life exist in so many diverse and exceptional forms? If life was created on the early earth, is it possible for life to be formed synthetically in a laboratory? Why has science thus far fallen short in such experiments? Finally, what is death, and is it possible to have life after death?
When confronting so many difficult and complex questions, it is very important to define terms. The most important concept to define in this case is ‘life’ and what it means to be living. ‘Life’ is used with two distinct meanings. Life is first a category, e.g. life on earth, or living things vs. non-living things. In this way life is used as a commonality among living things and a means of separation between the living and non-living. Life is also a quality of entities. Certain beings are described as possessing life. One sees objects as alive, full of life, or dead, non-living. It is life as a property of living things that requires defining, and where definitions often fall short. There are several common properties of living things. The exact specific properties that define life according to scientists can vary depending on texts, but the basic properties are consistent and there is no question that all living things share the same properties of life regardless of the textbook definition. All living things have structural complexity, meaning they are or have cells in constant dynamic motion. All living things also metabolize. Living things consume material and transform this material into energy in order to maintain their structure. Living things also have genetic systems. A genetic system encompasses the ability to pass on traits while allowing also modifications, involving (in life as we know it) protein synthesis through a process using DNA and RNA. Finally, all life exhibits growth and reproduction in some form at some point in living. Some definitions require that being subject to Darwinian Evolution be a property of life as well.
Regarding its origin, life first appeared on Earth between 3.5 and 4.5 billion years ago. There is some controversy as to how life first appeared on Earth. There are two possible means for the first appearance of life on Earth. Life either began on Earth, or began somewhere else and migrated to Earth. The migration of life to earth from elsewhere is called Panspermia. The possibility of life traveling within the solar system is commonly accepted, although the travel of life as we know it from further than the edge of our solar system is subject to doubt. It is known that of the basic elements of life, only hydrogen has existed since the beginning of the universe, so life as we know it could only have been formed many millions of years after the universe began.
Both the possibility of Panspermia and life originating on Earth require that life be formed from non-life at some point. Today, scientists can only find life forming from life. This is because the immense amount of life on our planet metabolizes all available energy before any pre-life form could gather it. This explains how life being created from non-life on today's earth would be very unlikely. It would be much easier for life to originate in a world with no life.
There are two possibilities for the formation of various lifeforms, natural selection or intelligent design. Natural selection is Darwin’s theory, or the theory that over time there are variations, a struggle for existence, and the entities pass on traits to offspring. The struggle for existence reinforces variations that are more favorable for reproduction and survival. Natural selection explains the diversification of species and, although difficult to test, could also offer a solution for how chemical processes could transform into primitive forms of life. The hypothesis of intelligent design states that there are some aspects of life that are too complex or irreducibly complex for natural selection to explain and that life must have been created by some “Intelligent Designer” or other life form that is different from what we know as life. Some of the things that are seen as irreducible include consciousness, language, and some basic faculties of single-celled organisms. Natural selection has yet to confirm the creation of life from non-life, which makes a hypothesis, such as intelligent design attractive, although the ability of natural selection to explain most of the features of diversification of life has not been disproved in many attempts to scientifically test important aspects of it.
When considering the origin of life, there are three crucial ingredients whose origins must be explained if the origin of all life is to be explained. All life requires a cellular compartment, a mechanism of metabolism, and a genetic system of some kind. The creation of a cellular compartment is quite likely over time as many chemical mixtures when agitated create bubbles with shells that appear equivalent to basic membranes. Metabolism poses some issue to the origin of life; however, there are chemical processes that regenerate with the help of inputs. In this sense the basic forms of metabolism are present in no living systems. The final ingredient is also the most difficult to explain. The genetic process, which involves DNA coding RNA that eventually produces proteins with the help of ribosomes, is extremely complex and intricate. The genetic process is also the most essential for mutation, a key factor in Darwin’s theory. Whereas one can imagine the metabolic process existing in non-life forms and slowly evolving into more complex processes, the genetic process is more difficult to picture forming by gradual process. The exact process of the creation of life remains a mystery, but natural selection offers a theory for life’s diversification that has not yet been proven false. Death offers further mystery in the science of life. Life is a quality of living things that leaves them when they die. Their body begins to die as no energy is returned to the system. Life as a quality of living things has no physical properties like matter, yet it clearly exists in living things. There are also mysteries as to the purpose of life in the universe. Stephen Hawking once called the human race, “…a chemical scum on a moderate-sized planet,” but are living beings more than just its chemical compounds? Many believe that life, particularly sentient beings, create meaning in the universe with their existence. Many mysteries of life remain, and with new discoveries come new perspectives. Genetics has offered many new answers to the formation of diversity among species and evidence of the commonality of all species, but many go unanswered, and may remain unanswered for centuries.