People who are self-conscious are likely to be relatively more objective than those naive folk who believe that the facts are the facts are the facts.
In reality man is a finite creature and all reasoning is conditioned to some extent by his limitations and experiences. This is as true for scientists as for musicians and other artists. Old beliefs control new beliefs. What one already believes to be true conditions all hypotheses from that point onward.
As Stokes puts it:
We have to stand somewhere while arguing; we always argue from some vantage point, from some perspective. In Thomas Nagel's words, there's no "view from nowhere". And when arguing about the vantage point (the scientific theory, for example), you must and on the very thing for which you are arguing. [Mitch Stokes, A Shot of Faith to the Head (Nashville: Thomas Nelson, 2012), p. 78]Those most self-deceived (or dishonest) are those who deny that they are "standing" at some particular vantage point, who imply that they are purely and absolutely objective. Science (actually scientism) is often claimed by the foolish or dishonest to be just such a discipline--so objective, so committed to just the facts, that there are no previous commitments. Science, it is claimed, is a higher order way of discovering and knowing the truth.
Consider this fantastic claim by atheist Josh Harris, who objects to those who want to discuss pre-existing paradigms as part of discussing the "facts". He argues that such notions lead "many unwary consumers of these ideas" to conclude "that science is just another area of human discourse and, as such, is not more anchored to the facts of this world than literature or religion are. All truths are up for grabs." (Ibid., p. 80. Emphasis, ours.)
It turns out, of course, that science is just another area of human discourse, as any perusal of the history of science will readily demonstrate. But acknowledging this makes science more reliable, more objective not less.
So we have people who believe in the Living God, and those who don't. In both cases they have been conditioned so to believe (by God Himself--since He is the all-conditioning Conditioner). Those who believe, if they are objective, will be aware of a cluster of life experiences, relationships, books they have read, personal tragedies experienced, or Christians they have known that predisposed them to believe in God as the Creator of the heavens and the earth, and, therefore, as their Creator to Whom they owe all things, and against Whom they have sinned.
Those who do not believe can likewise, if they are honest, point to life circumstances, upbringing, relationships, teachers and so forth who have predisposed them to Unbelief. Those that don't believe, if they are objective, will be aware of how they have been predisposed to Unbelief--and that these predispositions are just as powerful, if not more so, than any arguments about God's existence.
As atheist Thomas Nagel expressed it:
I am curious whether there is anyone who is genuinely indifferent as to whether there is a God--anyone who, whatever his actual belief about the matter, doesn't particularly want either one of the answers to be correct. (Ibid., p. 83.)