Some quotes from Stuart Hampshire
A man’s interests direct his perceptions, and his perceptions pick out the facts that are relevant to his interests
Our biases affect how we see the world, plain and simple. I only hope that our interests would include the truth.
As self-consciousness is a necessary prelude to greater freedom of will, so it is also a necessary prelude to a greater freedom of thought.
and…
A man becomes more and more a free and responsible agent the more he at all times knows what he is doing.
We need to pay attention not only to our surroundings but also to the environment of our minds. There are hidden corners, shadowy alleys, and subterranean caverns within our psyches that will continuously confound us if we do not investigate them.
We need to perpetually challenge ourselves to become better, more aware, and to transcend ourselves.
Finally, I’ll allow Nietzsche to have a say:
To translate man back into nature; to become master over the many vain and overly enthusiastic interpretations and connotations that have so far been scrawled and painted over the eternal basic text of homo natura; to see to it that man henceforth stands before man as even today, hardened in the discipline of science, he stands before the rest of nature, with Oedipus eyes and sealed Odysseus ears, deaf to the siren songs of old metaphysical bird catchers who have been piping at him all too long, “you are more, you are higher, you are of a different origin!”—that may be a strange and insane task, but it is a task
Skepticism, Properly Applied 