Then Pilate said to him, "Then you are a king?"
Jesus answered, "You say it, for I am a king. I have been born for this, and for this I have come into the world, that I should testify to the truth. Everyone being of the truth hears my voice."
Pilate says to him, "What is truth?"
In The Origin of Species Charles Darwin wrote, “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive slight modifications, my theory would absolutely break down. But I can find out no such case.”
There are numerous examples of irreducible complexity that have been discovered by modern science, for example the bacterial flagellum, the molecular machinery in cells and the complexity of DNA/RNA. The technology to make these discoveries was developed after Darwin's lifetime, so he could be excused for missing these. But, one obvious example of irreducible complexity that Darwin should not have missed is sexual reproduction.
Think about it. Male and female reproductive systems are so incredibly complex and are so very different from each other, yet they are perfectly complementary. The only logical starting point for sexual reproduction in the evolutionary scheme would be evolution from asexually reproducing organisms. This would require multiple branches of evolution over millions of years in very different directions. The interim evolutionary steps along each branch would have no reproductive benefit to the organisms until the evolutionary process had completed millions of years down the line. Between these multitude of evolutionary branches, there would need to be at least two that happened to be perfectly complementary and happened to be in the same location - the chance of all this happening is essentially zero. If sexual reproduction did indeed evolve from asexually reproducing organisms, then we should see abundance evidence in such organisms in the present and in the fossil record, showing their evolutionary attempts at producing these new reproductive systems, but we see absolutely no such evidence.
In The Origin of Species Charles Darwin never even addressed the starting point - how did life begin in the first place to be able to evolve? He just assumed the existence of living cells and then took his theory from there. But, the origin of the first living cell is the biggest challenge to the theory of evolution. The popular belief is that the first living cell came into being in a "primordial soup" billions of years ago. Time is meant to be the friend of the evolutionary process, but the real irony is that time is the greatest enemy of the chemical synthesis of the molecules needed for life.
For more information on this problem, listen to one of the world's top synthetic organic chemists speak on this: https://youtube.com/watch?v=ysEc8SdDLAs