Evolution

[Gabu]

Yes, in that I think it's the best we've currently got.

I'm not really sure about whether or not I believe evolution as it's currently stated is 100% true, though.  I've never examined the issue enough to say one way or another.

[Gabu]

We should also note that it is called the theory of evolution.

I like being skeptical as much as the next guy, but that's not a relevant or valid point at all.  Do you question the theory of gravity?  Theory has a different meaning in a scientific sense than in an everyday common use sense.

Considering that the "constant" of gravity has been disproven and replaced with a scale depending upon elevation, gravity is still considered to be a "theory."  That doesn't mean there isn't a force pulling you down, but it does mean that we don't fully understand it yet.

His point was simply that the fact that it's a "theory" essentially means nothing, because absolutely anything found in modern physics is a theory.  The fact that it's a theory doesn't mean that people don't think it's likely to be true or that there are viable alternatives that should be given equal weight.

Newton developed his theory of gravity that took altitude into account (which is still more or less accurate) around 1687.  It's not as if the notion is a relatively new one that gravity is not constant with respect to altitude.

[Gabu]

Gravity is not theory. It is fact. Mathematically it is expressed as the Gxm1xm2/r^2. We can test it and show that it is true. But no one has been able to create DNA from the primordial ooze. And while breeders can create new types of dogs through selective breeding, at the end of the day they still have a dog, not a cat or some other animal. It has not been proven that the steps necessary to get from ooze to man can actually happen, so evolution remains a theory.

Not quite.  Gravity is indeed a theory, and the reasons and explanation for it are not fully understood by scientists.  Newton's theory of gravity in the 1600s was very good, but not exact.  It was later revised by Albert Einstein in his theory of general relativity.  Pre-Einstein, gravity was thought to be this mysterious force between two bodies of mass.  Now that general relativity is in existence, scientists now believe that motion due to gravity is due to the curvature of spacetime from the presence of objects inside it.  It is entirely possible that our understanding of gravity may again radically change a century from now.

In short, to state that gravity is simply "a fact" is, well, false.  The attraction between two objects has certainly been observed in reality; however, scientists do not claim to totally understand this observation.  Likewise, mutations like those present in the theory of evolution (though on a smaller scale) have certainly been observed in reality.  Few debate the notion that micro-evolution is real.  It's the notion that we all evolved from single-celled amoebas that is not currently known as a fact.

In addition to Einstein's general relativity, it should be noted that there do exist other theories of gravity, as well.

[Gabu]

Gravity is not theory. It is fact. Mathematically it is expressed as the Gxm1xm2/r^2. We can test it and show that it is true. But no one has been able to create DNA from the primordial ooze. And while breeders can create new types of dogs through selective breeding, at the end of the day they still have a dog, not a cat or some other animal. It has not been proven that the steps necessary to get from ooze to man can actually happen, so evolution remains a theory.

In short, to state that gravity is simply "a fact" is, well, false.

In the Gabu universe do objects fall up? Do they accelerate at some acceleration which deviates measureably from the formula I posted? Did scientists in your universe not manage interplanetary travel because they could not accurately predict gravity?  If you want to look at the universe on the scale of galaxies you need Einstein's relativity, and if you want to look at subatomic particles you need quantum theory, but in the world in which you and I live the laws of motion developed by Newton 3 centuries years ago are very  accurate and form the basis of virtually all engineering calculations today.

As to evolution, have you ever seen a new species evolve from another?

You need to differentiate between observation and explanation.  Gravity is not the observed data that shows objects propelled upwards coming back down again.  Gravity is a scientific theory that attempts to say why that happens.  Objects came back down to earth long before the word "gravity" was in the vocabulary of science.  I think we're forgetting what this argument was all about: it was started when you asserted that gravity was not a theory, and I'm explaining why it is indeed a theory (and, in doing so, also explaining why the fact that something is a "theory" does not in itself invalidate it).

By the way, you might be interested to read this.  It's not as if scientists are just sitting on their butts doing nothing and expecting people to simply take the theory of evolution and of our ultimate origins on faith.

[Gabu]

When I look up gravity in my handy dandy American Heritage dictionary it tells me that gravity is a force whose magnitude is given by the formula I quoted earlier. The word "theory" is not mentioned. When I look up evolution it refers to it as a theory.

Is the American Heritage Dictionary suddenly an expert on all topics physics?  A cosmologist with a Ph.D whose lecture I went to see at UVic referred to it as the "theory of gravity".  I don't know about you, but it seems to me that a cosmologist would have a better idea than the people who write dictionary entries.

Did things not fall down before the notion of gravity came along that said that bodies of mass attract one another?