A posteriori attempts to assign odds to events do not produce meaningful results, although I can say that if the universe were not consistent in this manner, you wouldn't be around to remark at its consistency.
The Laws of Nature themselves give evidence of design, they are still in effect, and they are easily predictable and observed. Same with the processes of growth and change in the human body. Let's try applying some mathematics of probability to these fields of obervation and see if we get consistent results, shall we? Let's predict whether atoms will retain the same attributes for the next year or so, shall we? What keeps atoms that way? Can you explain this by some "chance" mechanism, or will you insist that I and the rest of mankind believe it is all by chance and call us all fools?
If your existence were completely a posteriori you would be a less significant than a fossil.