It is not as true for the critical thinker as it is for the faith-based thinker. The former actively learns to not do that. I've noticed in a few true crime stories, the detectives will refer to training they've had to suppress preconceptions when investigating and learn to evaluate evidence dispassionately. They understand the importance of bringing this principle to the process, as does the experiences critical thinker. I'm sure a little tendentious occurs anyway, but with multiple detectives all trying to minimize such a thing, their investigation becomes more objective and less dependent on observer bias.
The problem is the depth and breadth of the "preconceptions" that we use to determine what evidence is, and how valid it is. And how much is required to then overcome our inevitable bias. In nearly all your posts you write as if evidence were some objective existential phenomenon that you simply have to be willing to let lead you to a true conclusion. But it's not. It's a totally subjective determination based on what you determined to be "evidential" in the past. And in your case that's almost entirely material. That's your overwhelming reality-bias: materialism. Other people will determine other kinds of things to be evidential based on whatever their particular 'reality-bias' is. And it's ALL valid evidence depending on the reality-bias being used to determine it being valid evidence.That's all of us, and you, too. It's also happening in science, and philosophy, and art, and religion. Each method of investigating reality has it's own criteria for valid evidence, and for valid reasoning, that then become their own innate bias.
Now look at your comment again. Yes, we probably all do it, but one tradition actively seeks to minimize that, ...
They ALL actively seek to minimize it. They just use different methods and criteria for doing that, and for determining if they've succeeded or not.
"Evidence" is subjective, TO IT'S CORE, because it's all being determined by US. And we are the subjects causing the subjectivism. You think science is more 'objective' because it uses similar (materialist) methods and criteria to what you use to determine evidential validity and reasoning. But that in itself is just another big fat bias rendering itself unbiased. That method works OK when we dealing with very physical, functional questions. But it's useless and worse when dealing with more existential, conceptual, and universal questions. Philosophy tends to be the 'go-to' methodology in that realm of inquiry, but it becomes useless and worse when confronted with fundamental, existential irrationality. Because it's so heavily invested in the necessity of formal logic. And so on. All of our preferred methods are both based and ineffectual outside the narrow parameters of their 'reality bias'.
You keep making this claim that faith takes one further than strict empiricism. Every time you do, I ask you to say what that method has revealed to you that you think would be of benefit to others if they would just relax their standards for belief. And you never have an answer to that. So why should it be believed that there is any merit to taking that advice?
Faith and intuition are both based on trust and action, not on knowledge and explanations. You want it all explained to you in advance, but it doesn't work that way. Sometimes we have to make a choice and take action without knowing why or what will happen. In fact,we do this a lot in life. And we humans have an innate ability in that regard, because acting on faith and instinct tends to be much more holistic, quicker, and often more effective than science or philosophy. This is the realm of being better suited to the artist. A methodology marked by a combination of practice and courage, rather than plodding study and laborious experimentation. or endless debate and usually inconclusive debate. The artist just follows his desires and trust in his instincts.
You're conflating the real but as yet undetected with the nonexistent. Yes, people may have been unaware of bacteria or DNA or radiation at one time, but those things could all affect them nevertheless, and with the proper tools, they can be detected.
Do you really think all the mysteries are solved, now, and nothing more is affecting us that we haven't recognized and detected? Because that would be a very bizarre assumption given our history of profound ignorance.
The difference between something that exists, or is real, and something that does not exist is the ability of the former but not the latter to interact with other real things (things that actually exist). Most theists will tell you that gods and the supernatural realm are not detectible by any means. Is it a coherent position to say that something exists that is undetectable not just because the right machine hasn't been built yet to discern its presence the way the microscope revealed bacteria, but because it makes no impact on our reality?
We have no way of knowing what's real and what isn't, or what could be real and what couldn't be. The best we've ever been able to do is presume upon our own limited biases, as I've explained at the top of this post.