This is the strongest explanation I have, and helps to have an understanding of terms like “theory”, “evidence”, “science” and “proof” in scientific ways which I think you may believe you’re familiar, but you actually misunderstand, and it causes you to not fully comprehend evolution and perceive weaknesses which may not be there, or to have expectations based on claims it doesn’t make, or based on faulty or unreasonable expectations of science. But right now, it’s all I’ve got. Students take a semester to learn how scientists use these terms and why, and how peer review works, how evidence is evaluated, and how science actually rewards the discrediting of old dogma more than the reinforcing of it (look at the Nobel prize winners. You want to win a Nobel prize? Prove evolution wrong. Nobody’s been able to do it, and after massive attempts, people don’t bother anymore).
The concept of evolution, that animals could change and develop new traits over time, has been around for over 2,000 years. Ancient Greeks like Anaximander and Empedocles proposed that animals could evolve from one kind to another. Similar theories were developed by the Romans, Chinese, and ancient Islamic Scientists.
The problem was that while it was obvious evolution could be done if you had someone driving the evolution (a person creating new plant species by selecting the fruits and visible seeds they like and re-seeding those, or by breeding dogs). But in nature, nobody oversees this evolution, and thus it would be random. Since it would be random, and thus unsustainable the notion that evolution happened on a large scale was considered laughable.
Darwin didn’t discover evolution. That had been around for a while What he discovered was the natural process for doing it in an orderly way that made it sustainable over time. He called it “Natural Selection”.
Darwin made a second discovery, however, and this one terrified him. He discovered that the process of evolution and natural selection was so powerful that, if life had started from a common ancestor, it could, given enough time, literally account for all life on this planet. Doing more research, he became more and more convinced that not only was this possible, but that this was in fact what happened.
This terrified him, and turned his world upside down. He was a Christian. This was the last thing he wanted to believe or to be true.
But he felt his job was to go where the evidence led, to have an open mind. And this was where it led him.
Indeed, it didn’t lead just him there, but it also led a man named Alfred Wallace there (but just as Alexander Graham Bell beat Elisha Gray to the patent office by 4 hours, and so now nobody’d ever heard of Gray, Darwin published before Wallace, and thus gets all the credit, though Wallace reached the same conclusions)
With this new insight into evolution, radicle changes in understanding came. Many bones and fossils which had already been collected but we did not understand suddenly made sense. Tools found by Archaeologists like Boucher de Perthes where Homo sapiens were known never to exist suddenly made sense, as did entire colonies of “deformed” humans (they weren’t deformed, they were prehistoric). We were able to begin making a map of what species likely evolved from what – based on its capabilities and where it lived.
Using carbon dating and fossils (and how deep the fossils were buried as a reasonable indicator for how old they are) we were able to track the evolution of species to an even higher level of detail (and it matched what we could tell just by looking at the phenotype behaviors of species and by comparative anatomy, making 3 different fields of science, each independent of eachother, each capable of showing us this map, all agreeing with the view that we evolved, and agreeing how).
Using this, Darwin actually predicted several species which had never even been seen before. He began looking for the species, and died before they had ever been found. He thought they had gone extinct, but eventually we found them, and they looked and behaved exactly how he described, including a moth with a 2 foot tongue.
What you need to understand is that it would take very little to disprove evolution… Just one fossil that doesn’t belong, one thing that suggests human beings descended from reptiles (let me be clear, as opposed to common ancestor), one piece of hold over structure that doesn’t belong (Whales actualy have tiny legs-ball and socket joint. If they were created, why? But if they evolved, we know how and why, we can trace back when they stopped using them and when they got smaller and smaller. The entire history is already mapped out).
All this evidence was already conclusive enough to prove evolution true.
Then we discovered DNA.
DNA provided yet another line of evidence. By sequencing DNA, just like a parental test, we can tell where we are descended from. And guess what? In every species that we have sequenced, the genetic map (called “the tree of life”) matches the map that we had already developed.
If evolution were false, you’d expect DNA not to result in anything. Instead it produces a new map that perfectly concords with the one we have (and helped us fill in the gaps, shows us where to look for hissing species in the 8.7 billion total we’re trying to map… It’s a lot).
If Evolution is fallse, it simply would not be possible for all of these separate lines of evidence from fenotyping, comparative anatomy, archeology and fossils, as well as the DNA record, to each yield huge records that all agree with each other.
It’s not possible.
Yet that’s where we stand.
The evidence for evolution was overwhelming and sufficient to prove it before we discovered DNA (which shows the common ancestor DNA in all of us, and is traceable, and can be fiscally seen in the fossils, traced in migratory patterns in sedimentary layers… all of it… And whales have hip bones! And you have a tail bone! And we can trace how and where it came from, watch the evolution).
This is what makes it a “Theory” and a “Fact”. A theory in science isn’t a “hypothesis”, it’s an over arching collection of a mass of facts and data into a working system (Like Gravity is a theory, Or “Atomic” or “Germ” theory).
So first of all, by the time something becomes a “Theory” in science, it’s HUGE. It’s bigger than a fact (google it, get a dictionary, but this is important). And while small components of it may change, to become a “Theory”, it must already be accepted as true (again, like the Theory of Gravity. That’s not up for debate). The theory of Evolution simply isn’t contested anywhere in the scientific community. It’s a fact. It really is.
But because a theory is so large, it isn’t a single formula, and it’s not subject to a single proof. It’s a system. And you have to learn it as a system. You have to learn the claim and how it works, and if you refuse to do that (by, for example, pecking each component to death before you can actually try to piece it together and look at the whole…) you’ll never get it. But asking someone “Prove evolution”… It’s a theory, the strongest and most complex construct in Science (the goal of EVERY scientist is to invent a theory. They ALL want to make one. It’s immensely difficult). It’s not a “I can prove it in a couple of tweets” ESPECIALY to someone who has misconceptions, think that the science is out, many scientists don’t agree with it, or for some reason would otherwise rather it were not true.
Now you’ve said you’ve got an open mind. The truth is this theory was hundreds of years in the making, and was proved hundreds of years ago and EVERYTHING that’s come up since then has only made it stronger. That multiple, independent sciences ALL see the same picture…. And that Darwin got a pretty decent Tree of Life without ever having heard of DNA, that we made a GREAT Tree of life from Fociles, from other sources, then our DNA shows it ALL TO BE RIGHT. We DO have the common APE DNA but NONE of the Reptilian DNA, just like you’d expect. All the branches are right. Rabbits are where they belong, Trees, fish…. If Evolution were wrong, you’d expect the DNA to say so, give bad data, or data we don’t understand. Instead it duplicates it perfectly.
IT’s simply not possible any other way.
Thanks for your time.