They can be found with a little digging.
The thing about truth is that we may have it and never really know.
Science and philosophy are the tools we use to seek it, but we are left with the realization that we cannot know if we find it.
I can't speak for philosophy, but the strength of science is in knowing that what we find can only be tentative and the best answers we can come up with from what we have learned.
Philosophy uses logic and reasoning to come ever closer to what might be the truth.
Perhaps oversimplified for both, but the best you will get out of me right now.
But people will reject what is known in favor what they want to believe or desire all the time. They may be rejecting the truth, the most logical position or the best answers we can come up with, bur reject it they do. By now, most are aware that some substances can be addictive, but that doesn't stop people from believing addiction will never happen to them. It doesn't take much digging to find that not so mysterious fact.