What we take to be true is what we believe. What we believe is based upon our…
What we take to be true is what we believe. What we believe is based upon our perceptions. What we perceive depends on what we look for. What we look for depends on what we think. What we think depends on what we perceive. What we perceive determines what we believe. What we believe determines what we take to be true. What we take to be true is our reality.
Reality, as we live it, is a loop rather than a straight line. We believe what we perceive, but we perceive according to what we look for, and what we look for is shaped by what we already think. Each step feeds the next, and the circle closes on itself, so our picture of the world keeps confirming the assumptions that produced it. The quote does not deny that a world exists. It says that the world we experience as "just how things are" has been filtered by us far more than we notice.
This fits Bohm's broader outlook. He was a physicist who questioned fragmented ways of seeing and stressed wholeness, and he later wrote and spoke about how thought shapes experience while pretending to merely report it. The exact wording is widely attributed to him, though I can't point to its original source.
In everyday life, imagine someone convinced that their coworkers dislike them. They will notice every curt email and forget the friendly ones. Knowing the loop, they could deliberately look for evidence against their belief, or simply ask a colleague for honest feedback, and see what changes.