Maybe I'm dating myself here, but the phrase "The Truth is Out There" reminds me of the '90s television show, The X Files which, I believe, makes analogies here that I can use to speak to this prompt. The premise of the show was that two FBI agents, Fox Mulder and Dana Scully, sought to prove and alternatively disprove the theory of the existance of paranormal activity. Agent Mulder theorized, based upon personal experience and collected evidence, that paranormal activity existed. Agent Scully, on the other hand, sought to disprove Mulder's theories (based on her own beliefs) and was unable to see the parallels between what they encountered (evidence) and Mulder's theories. Her personal beliefs (or disbeliefs) got in the way of her seeing what Mulder viewed as the truth. Eventually, Mulder was able to convince Scully that his theory was true. The truth was out there for him, he knew what it was, but it took a while for him to prove it. And in the end, reshaped what Scully saw as the truth.
The same holds true in real life. I agree that there is truth out there, but it is relative to the person seeking it and, therefore, impossible to prove conclusively to everyone. Even scientific theory cannot present absolute truths. There is always another means of testing, another antidote, another species found that can alter or disprove a truth.
Personal prejudices and beliefs sometimes get in the way of finding a truth, or can alter it. Be it a personal belief or someone else's. Conversely, the same prejudices and beliefs can, in essence, become truth to the person holding them and, through the use of effective communication or propaganda, can become a widespread truth to the people hearing it.