God Riddance

 The Argument from Biogenesis

 

The Argument from Biogenesis contends that it is either highly unlikely or impossible for the first life to have come about naturally. As evidence of this, creationists will often cite the “Law of Biogenesis”: Life only comes from life. What they forget is that this applies only to modern day life, because of its complexity and because it exists in the presence of other life-forms. Yes, maggots do not form themselves from raw meat, as people once thought. But that does not mean that the very first life could have only been created by God. Creationists will often point out that even the simplest, single-celled organisms alive today are far too complex to have just fallen together in some primordial soup. But no scientist alive today believes that life began with a cell as super-complex as today’s cells are. Scientists usually begin explaining the origin of life by explaining the origin of simple, self-replicating molecules, and then by explaining how these molecules evolved into the first cells.

Another popular misconception is that since we don’t see new life emerging from non-living matter today, it must be impossible. Charles Darwin answered this objection in a letter to Joseph Hooker:

 

“It is often said that all the conditions for the first production of a living organism are now present, which could ever have been present. But if (and oh! what a big if!) we could conceive in some warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity, etc. present, that a protein compound was chemically formed ready to undergo still more complex changes, at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed.”

 

In other words, all the substances of which life is made, such as proteins and nucleic acid, are consumed by modern day life-forms before they have any chance to combine into something we might call “life”. Of course, no living things were around to eat up biological molecules before life originated (Obviously!), so this is not an issue for Origin of Life Scenarios.

Another, more commonly heard argument is that life cannot originate from “mere chemicals”. This is simply a confusion over what life is: Life is nothing but the chemicals it is made of. We only call certain collections of chemicals “alive” because they can reproduce, they have metabolism, and they can evolve.

Most Intelligent Design Creationists have realized that they cannot argue that a natural origin of life is impossible, so they simply take the alternative route of arguing that it is improbable. The same general fallacies plague each and every one of these arguments: The creationist either repeats false information or assumes something he does not know.

For example, a classic argument against the origin of life is that life only uses left-handed amino acids, while origin of life experiments produce equal amounts of right-handed and left handed amino acids. It is further argued that a chain of completely left-handed amino acids forming from a mix of right and left-handed amino acids is so improbable that it would not happen within the age of the universe (The odds of each amino acid being left-handed is one out of two, and creationists usually assume that life had to begin with at least one complete protein, which requires dozens of amino acids). However, creationists ignore the fact that scientists have discovered a number of plausible mechanisms to solve this dilemma. For instance, scientists have discovered that meteorites contain a higher percentage of left-handed amino acids (which suggests there is a natural process for generating more left than right-handed amino acids)[i].

Yet another classic example of faulty reasoning in origin-of-life probability calculations is provided in Michael Denton’s classic anti-evolution text, Evolution: A Theory in Crisis. Denton asserts that the first cell would require “at least one hundred functional proteins to appear simultaneously in one place”[ii]. Each protein, according to Denton, would have to be at least twenty amino acids long; Furthermore, “unique sequences” of these amino acids would be quite rare: the chances of such sequences coming together by chance would be about 1 in 10²⁰. Multiplying the number of proteins times the independent probability of each one forming, Denton figures the odds of the first cell forming by chance are about 1 in 10²⁰⁰⁰.

So what’s wrong with Denton’s estimate? In a word, everything. For example, he assumes that proteins would be needed to synthesize and maintain the cell’s membrane[iii]. These proteins he assumes necessary are a large part of what makes up his hundred-protein estimation. But lipid membranes have been observed to form under plausible conditions simulating the early earth[iv]. Why would a cell need to create something already present in its environment? Furthermore, why would the first cells have needed to maintain their cell membranes? The first cells simply had to survive long enough to leave behind a few offspring. Cell maintenance could be neglected, and eventually evolve to give a competitive edge to later generations.

Denton’s estimations are further degraded because he assumes that one, and only one, sequence of amino acids will function properly. This is absolutely wrong: Proteins often function just fine when one amino acid in their sequence is substituted[v]. In fact, there is an enzyme called Cytochrome C which shows a wide range of variation between species and yet still performs the same task[vi].

So, how did life start? We don’t yet know. There are plausible ideas being tested (as I discuss in chapter 9), but it will most likely be many years before we have a detailed explanation of how the first life came to be. In the meantime, do not be fooled by creationist calculations alleging to show the origin of life improbable. Richard Carrier[vii], Ian Musgrave[viii] and David Deamer[ix] have written excellent essays, available online for free (see references) which do a more than adequate job of exposing creationist fallacies.

---