Origin of life on Earth
The origin of life on Earth has long been a hotly debated subject in the Western world, with proponents of various Creation theories contending with proponents of unguided evolution. The two main branches of Creationism are put forth by the Young Earth and Old Earth creationists. Advocates of materialism and atheism support the hypothesis of physical science that various small changes have accumulated over time to produce entirely new kinds of living things: one-celled organisms evolved into plants, fishes, and land animals.
The Young Earth view stipulates that the entire planet Earth has existed for less than 10,000 years, that it was created by God, and that God created every kind of living thing himself at the start of that period. The basis for these assertions is the Holy Bible. This viewpoint is generally regarded as relying primarily on religious faith, although some Christians maintain that Young Earth creationism is consistent with modern scientific knowledge (see Creation Science). Those who feel that physical science can (or should) explain everything reject all three aspects of Young Earth creationism.
The Old Earth view may be compared and contrasted with the Young Earth view. What is different between YE and OE is that OEC disagrees about the age of the Earth, agreeing rather with the view of physical science that Earth has existed for over a billion years. OEC agrees that God created it, though.
- While OE agrees that God created the earth, OEC parts company from YEC about the age of the earth, accepting the view of physical science that the earth is over a billion years old.
OEC also agrees with mainstream geology and biology that the various species of life came into being at many different times over the last few hundred million years. Some OEC believe that God himself created the new species, while others OEC believe the process to have been automatic (i.e., natural or unguided). OEC generally accept that natural selection would automatically weed out any new species which were not viable.
Atheists and materialists reject both schools of Creationism; indeed, some fail to acknowledge the difference between OEC and YEC, either outright ignoring the existence of OEC or simply lumping both schools of thought into one monolithic entity. (Ironically, OEC outnumbers YEC by a 5 to 4 ratio.) Physical science approaches the origins question by asserting the validity of the fossil record, which supports the idea that various species of life first appeared at different times over the last few hundred million years. The cause for these appearances is a combanition of two factors: natural mutation, caused by cosmic rays and so on, and the (unguided) process of natural selection. The view they support is called "unguided evolution" by opponents, but supporters simply call it "Evolution". Supporters of evolution either explicitly deny that God had anything to do with it, or surreptitiously avoid any mention of God as a possible cause. Evolutionists nonetheless have been extremely vocal in denouncing Intelligent Design as "pseudoscience".