Doesn’t the Bible teach that people in early days of creation (such as Adam and Eve, Noah, etc) had long life spans: Some even had life spans that spanned to 900 years old? I mean, I let it slide that The Book of Job depicts Job as living to be 140 because the book was not meant to be taken as history (but rather as poetry), but I’m having a hard time accepting the idea that people in biblical times had life spans that spanned more than 100 years. I still consider myself a Christian, but I want to live by the principal to not bear false witness to the truth (especially science such as the theory of evolution, which I do accept). I’ve looked at other Christian websites that try to explain that, but none of their explanations satisfied me. Is there any truth for this idea, or it supposed to be symbolic?
You should decide for yourself how to take the biblical statements about ages. Perhaps these ages are symbolic, but personally I do not think so. This is not a huge issue to me. Important issues are things such as whether or not Jesus is in fact God, as he claimed, how one is saved, how God wants us to live our lives, whether or not the Bible is inspired by God…. things like that. The question of the age of people who lived several thousand years ago is not a big theological, doctrinal or practical issue as far as I am concerned.
Having said that, I do believe that your question is a perfectly reasonable one to raise. What is the deal with those long ages? First of all, please understand that I believe these things, not because of the scientific evidence, but because of faith in the Bible. I have learned over the thirty plus years I have been a Christian that it is always wiser to trust the Word of God–the Bible–that to reject it, even if there is something I do not understand. I believe in heaven, not because of the evidence, but because the Bible says that there will be a heaven. I believe that Adam and Eve lived, not because of some sort of archaeological or even DNA-based evidence, but on the good faith of the inspiration of the Bible. I believe that Abraham lived well past 120 years because the Old Testament, specifically Genesis, which has every sign of being inspired, says so! Period!
Scientifically, how could these longer lives have happened? I will have to admit that I do not know, but let me provide my own personal speculation, and you can judge my speculation for what it is worth. I believe Adam and Eve were created in a more perfect form than ourselves. I believe that mutations happen and that the vast majority of mutations are either neutral or harmful. It is reasonable (but definitely not proved from science!) that the first created people with a soul and a spirit lived longer, but that as humans devolved genetic diseases and other genetic defects resulted, including defects which reduced our potential life span occurred. That is how I view this question.
I am sorry that all I have to offer is a reasonable but not scientifically verifiable explanation, but it is worth bearing in mind that part of the Christian faith is the need to have faith "in things which are not seen." Obviously, the Bible does not provide scientific explanations for everything. In fact, it provides scientific explanations only very rarely. I hope this helps.