Francis Crick (co-discoverer of one of the most important discoveries of 20th century biology) arrived at the theory that life could never have evolved by chance on planet earth."One need only look in virtually any reference text to quickly find that the earth is thought to be some 4.5 billion years old.
To illustrate, suppose there is a burning candle sitting on the table. This can be calculated if the candles burn rate and original length is known.
However, if the original length is not known, or if it cannot be verified that the burning rate has been constant, it is impossible to tell for sure how long the candle was burning.