TED Conversations

Milton Fuller

This conversation is closed. Start a new conversation
or join one »

Why is evolution considered a fact?

A key component of evolution is spontaneous generation. If Pasteur refuted spontaneous generation in the 1800's, why is evolution considered a fact? ,


Showing single comment thread. View the full conversation.

  • thumb
    May 9 2013: Hi Milton,

    Part of why this is not an easy subject, is because it is hard to agree on the ground rules.

    Let's agree on terms first. Evolution is change. For a star evolution means consuming its reservoir of hydrogen fusing it into helium, and then switching to a different reaction when the fuel runs out. For a living thing evolution means changes that will give rise to a slightly different kind of offspring by means of changed dna. Example: we must get a flu shot every year because the flu virus is not exactly the same virus that existed last year, it evolved

    Darwin proposed a theory to try to explain this change (this evolution). His theory is called Natural Selection. Sometimes this theory is called theory of evolution but that adds to the confusion.

    So evolution is an observable fact, and Natural Selection is a theory attempting to explain how evolution arises.

    Now, scientific theories are not all-or-nothing: you can use a theory within a limited scope knowing that beyond certain point it fails to describe the observed phenomena. One can fly a rocket to the moon by using Newton's theory of gravitation, even if it has been proven to be incomplete and superseded (encompassed) by Einstein's General Relativity.

    How do you test a scientific theory? you take it's predictions and you try to find repeatable examples that do not behave as predicted. That proves that the theory is incomplete but that does not render the entire theory invalid. There are many areas where experiments agree with the theory of natural selection, and the more such examples we find, the more "solid" it is considered.

    I am not sure i agree that a key component of evolution is spontaneous generation "a la Pasteur". I would say that the kind of spontaneous generation that the theory of natural selection calls for, is the spontaneous arrangement of chemical compounds into compounds that could copy themselves, way before dna is even in the picture

    I hope i did not confuse things more

    • May 9 2013: I agree. The biggest mistake when someone uses spontaneous generation in regards to evolution is to believe that a bacteria, or a paramecium, or a housefly can spontaneously come into being from nothingness or from random chemicals in a soup. This has been rejected by the theory of evolution. However, we have seen in the laboratory that when you have the correct types of organic molecules in an aqueous solution and you pass an electrical charge through it (much like lightening striking a primordial soup) you can create a lipid or glycolipid membrane very similar to a cell membrane. In this situation you could say that spontaneous generation of this new molecular composition has occurred. The biggest problem is when people bring their preconceived notions of the universe with them to this discussion. Those that believe that the Bible is the ultimate authority will never be able to acknowledge that what has occurred could lead to any life forms, let alone higher ones. Those who are avowed atheists will never be able to acquiesce to the idea that this could have been set in motion be a deity. It is neither here nor there. The universe runs by a set of rules - it has too. It can not have arbitrary rules that come and go and change. Therefore, when we make theories like Natural Selection we are looking for those rules so that we may understand the universe. Whether you believe a deity set them into motion or not, they must still exist.

Showing single comment thread. View the full conversation.