Yes in 2 words, science and logic.
For example if it happened that your nose is designed to be close to your buttock then i'll be an atheist, maybe it happened one day millions of years ago and the offspring committed suicide before passing their genes to the next generation.
The reason why our nose is on our face rather than our but is actually profoundly simple.
Evolution isn't just random massive changes over short periods of time but simple to complex changes made one mutation of a gene at a time. The reason why we have a nose on our face and not on our anus actually starts out when we were incredibly simple and probably microscopic beings. We developed a mouth. Before a brain we probably developed a mouth. This gave us a more effective entry way to obtaining food rather than just absorbing it through our membranes. As a multi-cellular organism. Some animals lost their mouths along the way and some retained them. But having a mouth is a distinctly animalistic trait. There are no plants with functional mouths in the way way we have.
What does this mean? well it means that in order to find food and get it to our mouths it became advantageous to get more and more nerve cells to help "feel" around for food and get it in the mouth. Those that did not have as sensitive "heads" (though it probably isn't a defined head yet) would not have been as effective at surviving and therefore were less "fit".
So now we have an ever accumulating bundle of sensitive nerves accumulating near the head. It is still somewhat debated, but well supported, that this was the earliest form of a brain. With ever increasing and ever more complex bundles of nerves at this same area with an intention of getting food into the primitive mouth we get more chances for "sensory" nerves. The eye for example has evolved independently several times in several species throughout the world. Its a simple functional way to obtain information around us to better obtain food. Other sensory organs developed as well into our main 5 senses we have today.
So this bundling of nerves at our "mouth" eventually developed into the brain and other sensory organs. It would have also been evolutionary advantageous to have our "butt" or whichever way we got rid of excrement be as far from our "mouth" as possible to keep the chances of consuming our own excrement to a minimum. Since our sensory organs developed from the bundles of nerves near the mouth we develop a head with a nose on it and an anus to spew excrement at the other end.