If TE is true, then how did sin enter the world?

I can not grasp the fact on how sin enter into the world without the fall of Adam and Eve (Or rather their existence).
Dose anyone care for elaboration?

Most evolutionary creationists don't deny the reality of the Fall. However, there need not have been a literal Adam and Eve in the Garden of Eden for humanity to have become sinful.

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We can allow satellites, planets, suns, universe, nay whole systems of universes, to be governed by laws, but the smallest insect, we wish to be created at once by special act.

-- Charles Darwin

I think that Adam and Eve were either:

A.) The first individuals to reach sentience, or self-awareness and cognition on levels that would be considered human today.

B.) Adam and Eve were allegorical and represented the first communities of primitive Homo sapiens.

Either way the Fall still occurred. It probably was just groups of people instead of individuals.

Here's a thought.

About 350 years ago, Blaise Pascal, a great thinker, an early scientist, and a Christian, wrote this in his famous Pensées (translation by W. F. Trotter):

Pensées is a defense of Christianity. In a lot of it, it is hard to make sense out of what he is saying (at least for me). But it is full of nuggets, like this, that make the slog through it, well worth the trouble. The quotation here led to an "aha" moment for me.

Think of it. Throughout our evolutionary history, from slug to modern consumer, we looked after ourselves first. We had to. We could not survive without it. But we were not, at first, sinners. We were not sinners because, to be a sinner, you have to have knowledge of good and evil - you have to have a conscience.

So, whether you view Eve's eating of the fruit of the tree of knowledge of good and evil as something that literally happened, or as a metaphor for the awareness of morality which humans acquired, and which animals do not have, it makes sense that the fall was synonymous with understanding good and evil.

First, the Adam and Eve story is an allegory. You have 2 characters -- Dirt and Hearth -- who get cut off from God. They are meant, like most allegorical characters, to stand for a much larger group. In this case, all humans.

Second, how did Dirt and Hearth get cut off from God? By disobeying Him. Why did they disobey? Because they placed their desires above God's desires. IOW, they were selfish.

Well, guess what? Natural selection leads to selfish individuals. Remember, the unit of natural selection is the individual and natural selection picks individuals that do best in the competition for scarce resources. Any cooperation must also result in a benefit to the individual. Any individual that only does what other individuals want, to the detriment of itself, cannot be selected. Instead, helping other individuals will cause that individual to do less well in the competition for scarce resources and it will die without offspring. Any alleles for pure altruism are going to be weeded out of a population.

The "Fall" -- selfishness -- is embedded in our very genes by the process God used to create us. We are programmed to put our interests and needs above those of God.

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"If sound science appears to contradict the Bible, we may be sure that it is our interpretation of the Bible that is at fault." Christian Observer, 1832, pg. 437

"Christians should look on evolution simply as the method by which God works." Rev. James McCosh, theologian and President of Princeton, 1890