This is from a post by Biblical Creation & Apologetics Ministries: “Because these sediment layers can be many hundreds of meters thick, and because it’s assumed that sedimentation rates have always been slow, secular scientists believe the sediment deposition required many millions of years.”

“because it’s assumed” Human’s assume automatically. This is how we add to what God is saying to us. However, we don’t have to add to His Words, whether He is speaking through Creation or through Scripture. The Holy Spirit will reveal to us where we have left reality and have gone to the world of make-believe through our hidden assumptions. We must pray that He demolishes the strongholds of our minds as He leads and teaches us moment by moment throughout our lives. We must not artificially limit God with our assumptions.

Assumptions quickly are converted into presuppositions. Assumptions are suppositions. They are things we suppose, yet we don’t know them. We just treat them as if we know them. Then, we forget that they were assumed or we never become conscious that they were assumed. They seem to be real. So, we add them to our worldview, our conceptual inner world. The problem is that once these assumptions become part of that inner worldview, they seem real. They are make-believe, but they seem to be part of reality. We have lost touch with reality and instead are dealing with a land of make-believe within our minds. This happens to Christians and to skeptics alike. These concepts are strongholds in our minds. We look for ways to strengthen them up, and we’re able to strengthen them through confirmation bias. Groups of like-minded people gather together for the purpose of strengthening their confirmation bias. Group-held confirmation bias is even more difficult to overcome. We see this among skeptics. We see this in Secular science. We see this in denominational doctrines that add to God’s Words.