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Wednesday, September 09, 2009

Logical Practicum 2 - Evolution part 2

Let's have a look at the terminology surrounding the debate, and understand fully what's going on.

Science comes from the Greek word scientia, which simply means knowledge. Previously also known as natural philosophy, science is simply the body of knowledge we have built up about the world (the universe, really) and what we understand of the way it works. Traditionally, the main branches of the sciences are physics, chemistry and biology, and in a general sense everything else we call science can be expressed in terms of these three branches.

The scientific method, which is the single 'trusted' method of adding new things to the sciences, is a simple one;

  1. You observe a certain phenomenon, or certain phenomena. You notice a certain pattern.
  2. Based on your observations, you make a conjecture of why this pattern is so. This is called a hypothesis. It is important that your hypothesis is falsifiable - i.e. can be proven false. This is not to say that it will be proven false, but that there is at least one condition that, if true, means your hypothesis is wrong. This is important because the next step...
  3. You devise, carry out, and document rigorous trials to test your hypothesis true or false. These trials are called experiments. The purpose of these experiments is to see whether your hypothesis can identify result Y given conditions X, basically.
  4. If your hypothesis is shown to correctly associate outcomes with the starting conditions (i.e. has high predictive value), and everyone with your documented experiments can replicate the results, and for any given value of X can correctly provide the correct value of Y (within experimental error, of course), then it is no longer a hypothesis (which is an unproven conjecture), but a theory. Theories are anything but unproven; theories have withstood the test of time and varying conditions, and almost always provide the correct answers.
There are two underlying assumptions behind the scientific method; there is ceteris paribus, which means 'all else being equal' (and so you must control the rest of the variables during the experiments), and there's cause and effect, which simply means (a) for every effect there is at least one cause, (b) the cause comes before the effect and (c) causes can be (but are not necessarily) themselves effects. See how the scientific method works now? A hypothesis is simply saying that ceteris paribus, A -> B, where A is the cause (or causes) and B the effect(s).

The term evolution, as is understood in evolutionary and Darwinian biology, is referring to the change of one species into another over a (usually epochal) period of time. It looks at how new organs and traits can arise that differentiate the ancestor species from the descendants, and the descendants from each other. This is also known as macro-evolution. It is important to note that evolution is described to be a random, undirected process - i.e. it does not require a guiding intelligence to have it started or kept going. The current favoured mechanism for evolution is mutation, which is the process of transcription errors in genetic replication.

The term natural selection is the process through which a species adapts to its environment. Essentially, if an individual of that species exhibits a trait that is more favourable in a particular environment, then it is likely to live longer and produce more offspring than a comparable individual without that trait. The offspring, in turn, if the trait is a genetically determined one, will also live longer and produce even more offspring. Eventually, the species in that environment will have far more individuals with that trait than not, and hence, the trait seems to have been selected. This is also known as micro-evolution.

Creationism refers to the work of a Creator that designed and formed all living things. A creationist believes that far from life being a random and undirected process, Someone deliberately designed, developed and set loose the entire ecosystem in one go - not necessarily in an instant, but within a very rapid period of time.

Okay, so why is evolution against all logic and common sense? That comes up in the next part of the series.

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