How do you know that you are not just confirmation biased to fit your life into the presumption "there is God"?

Let me try to respond here using quotes paraphrased likewise from a source that you may not want to read, but it is stated without any question on the part of the author of the source that indeed GOD IS, and made Himself known through the source that clarifies HIS position . This source asks the human beings, to see if their 'idols' can do anything, i.e. forecast the future, accurately, do anything of greatness or of power to show that they exist . The answer in response is 'NO they can do nothing and are nothing " Instead they are 'created by human hands and cannot accomplish anything at all. " Human reasoning not withstanding being that it came from this source i.e. GOD, and is only alive because GOD has allowed this human kind to live. The physical evidence that you want via science, can be proven only through the Created human beings who are scientists themselves. This source has a place where it is revered and honored in many ways. It is called Church ! God established this place through human beings, and made known His presence in many ways through the older portion of the book that was published many generations ago. The ones who are referred to as "Jews" are your physical evidence of God, though many are "blinded in their reasoning abilities to accept Him, that does not deny His presence" . If you will allow yourself to be humbled, and take a long look at the book of Isaiah, in the Old Testement you can read about a person by the name of Cyrus who was called by God to do His will, even though Cyrus himself did not actually believe in God, he still was used by God to be the servant to do His will. Cyrus was a ruler in Persia that is identified by his own name there in the book of Isaiah, and was prophsied about 150 years before he was even born. If you will read the history of his even being alive and what happened to him, you should be able to see that it is God's hand that was at work back even then as well as many generations before then. You can look up Cyrus and see that he was a real person who was helping the Jews, in many ways, and highly regarded by them, in secular history about him even. But in Isaiah you can actually read what God had him to do, and the history of what he did is recorded in secular history and verified through the Scriptures that prophesied about him many years prior to his being born. I know that is not the 'kind of science' that you wanted to read but it is a recorded fact of the physical proof of God's working in the history of the Jewish nation. If you want to have physical science proof, I would suggest that you allow yourself to go to the website of www.answersingensis.org, and check it out, they would be more than happy to give you many scientific responses to your questions . They will be fair with you and they have dealt with many skeptics and aithiests as well. They also have a museum that is in Hebron Ky, that shows many things that are of scienitific nature explained so that the layman can understand, and have an extensive bookstore where many forms of material are available with many books, dvds, and so on to help you understand the existence of God is indeed real. I hope that you will venture forth there for your own sake.