If I had to give one reason for why I disagree with religion and its view of reality, it would this:
It is true that I make some assumptions. I assume that I exist. (I think therefore I am) I also assume that the universe exists based on my observations. It is true that my observations could be wrong, and that we are all just brains in a jar, or in the matrix. It is true that since I don’t know the future I can’t be absolutely 100% positive a ball will fall when I drop it. These are the shortcomings of observation.
Yet even with these shortcomings, religion and observation’s views about reality are not equal. Simple stated, observation produces practical benefits that religious belief does not. A thousand years ago the majority of human population was busy trying to produce enough food to keep from starving, and they often did. Nowadays, through the application of observation, 2% of a first world country can supply enough food to feed the other 98% of the population. A thousand years ago we didn’t know why the moon moved in the sky. Now we know, and not only that, we’ve traveled there and returned home safely. Two hundred years ago we didn’t understand what caused infections and disease, now we have anti-biotics and modern medicine that save thousands of lives daily. All of these advancements were the products of applied observation, science. Unless you live in a cave (which you don’t since you’re on a computer reading this) you use the benefits of science everyday.
The history of the relationship between science and religion is a history of religion making claims, only for science to come along and disprove them. This is simply because religion was originally invented to explain the then unexplainable. Why does it rain? The gods make it rain. Why does the sun move across the sky? Ra in his sunboat moves it. Why are there seasons? Because Persephone ate from the fruit of the underworld. How did life arrive on the planet? God made it. Why are there so many languages? The tower of Babel. These are just a few basic examples but the list goes on and on. The religious understanding of how reality operates is skewed in many areas, from medicine, to anatomy, to astronomy, to physics, to biology, and chemistry.
Yet religion can hardly be blamed for this. The sacred texts of the world’s major religions were written centuries before the advent of the scientific method. They did the best with what tools were available. So given this pattern in the history of science and religion’s relationship, I feel it is reasonable to assume the pattern will continue; much the same way that based off of previous observations I can predict that a ball will fall when dropped. This is related to the idea of the “god of the gaps”. The idea behind “god of the gaps” is that god resides in science’s gaps in knowledge. Even Newton reached a point where he couldn’t go any further and declared “god did it”. Yet since the advent of science these gaps have been slowly filled. Everyday the gaps that god can live in get smaller and smaller. There is nothing to suggest that the trend will not continue.
<Edit> Afterthought: I forgot to mention the complete lack of evidence for the existence of any supernatural beings. There is just as much evidence for the existence of Ra as there is for Yahweh, zero. Now I’m not saying they can’t exist. If I did I would be making a positive assertion which would shift the burden of proof to me. (Despite the fact that it is impossible to prove a negative) Yet as long as people claim that being X exists, they have the burden of proof. The bigger the claim, the bigger the amount of proof required. Claiming that there is an all powerful, all knowing, invisible being(s) in the sky is a huge claim. You use this same logic everyday. If someone said they had a diamond the size of a car in their backyard, you’d want to see it. Our legal system works off of this same concept. Innocent until proven guilty. The prosecution makes the positive assertion that the defendant is guilty. It is up to the prosecution to provide enough evidence to prove their claim. Until guilt is proved, the court operates under the assumption of innocence. Religion is no exception.
To tie it back to the original post, people often try to claim natural things in the world as evidence for their god. Even if it was evidence for the existence of a higher power, there is no reason to then attribute that higher power with all the attributes the religious do, i.e. all-knowing, all-powerful, loving, intervening in human affairs, etc. The funny thing is that the things the religious have claimed in the past have slowly been explained by science.
Occam’s razor states that when presented with two competing explanations, the one containing the fewest superfluous entities is to be preferred. The naturalist explanation always has the fewest superfluous entities, and better yet is demonstrate-able. From these observations we can learn about how the universe we live in actually works, and then take that knowledge and apply it to better the human condition.