If over 600 years ago you went with the popular flow and believed the Sun revolved around the Earth, that belief might not present too much of a problem for you, unless you planned on going to the Moon or accomplishing some other great celestial endeavor. But if your challenges were more down to earth, as they were for explorers and adventurers of the pre-Renaissance age, then other beliefs of your age would act as obstacles and perhaps stand in your way of your pursuits.
For instance, if at some time in the distant past, you wanted to travel across the sea to explore a new land, or find a new route to an old one...or simply set sail to see what's "out there"...a major belief of your time that could stand in your way, if you let it, would be that the Earth is flat. Such a notion might keep you from your journey, for fear of sailing over the edge into some great abyss of who knows what (which for the most adventurous might be reason enough to sail off). However, if you did not subscribe to this belief of a flat earth---for whatever reason...ignorance, reason and/or evidence to the contrary or simply your own intuition---then you might not hesitate to embark however far out to sea.
Such untruths and limitations in belief are all around us, and all the same may limit the extent of how far in life we travel, even no matter how much we try to get there.
For instance, if we still subscribed to the old geocentric, or earth-centered view of the universe, we could not get to the moon or other planets, no matter how powerful our rockets...because the mathmatics, as developed under the geocentric view, would not be accurate enough to accomplish the task. It would be akin to asking a marksman to hit a mile-away bullseye with a misaligned gun sight...and where each shot knocked the sight again out of alignment such that there could never be enough adjustment to get it right.
So if untruths or limitations in belief limit the extend of our travels...or in other words, put contraints on the possibilities in our lives and the potentials available in reality, then what might be the great untruths or limiting beliefs of our age, the beginning of the 21st century?
One path to anwering that question lies at the turn of the 20th century...where the theories of relativistic and quantum science began to take shape through the minds of men like Max Planck, Albert Einstein, Niels Bohr, Erwin Schrodinger and Werner Heisenberg just to name a few of the big ones.
Parallel to the development of these new theories, were other ideas working in concert, paving the "new" way for the science of our age. Here men such as Alfred North Whitehead, Carl Jung and Pierre Teilhard de Chardin, each working in their own particular field...articulating old notions of mind in a new ways... developed the concepts of processphilosophy, the collective unconscious and noosphere respectively. These developments drove the final nails into the coffin of material-mechanistic science.
Further exploring this new way, then daring beyond its outermost reaches were scientists such as David Bohm and Karl Pribram, who would finally bury the coffin of the old material-mechanistic science by presenting new models of reality in the form of holography or holonomic theory.
A number of other great thinkers of the mid-20th century simultaneously acted as trailblazers and pall bearers in this grand procession of discovery as it layed old notions to rest, or at least grounded them where they belong. Joseph Campbell offered keen insights into the power, purpose and primacy of mythos in forming what we call reality, thus likening life to the hero's journey...while Aldous Huxley's personal explorations and writings helped inspire the revival of shamanism in Western culture.
Today, at the start of the 21st century, the beginning of the third millennium and, by all accounts, the dawn of a new age, we stand on a threshold of changing thought, the likes of which can be compared to the dawn of the Renaissance some 500 years ago...only this revolution is even bigger. In a way not yet completely articulated---though maverick explorers such as Terence McKenna, Rupert Sheldrake and Juan Maldacena have pushed us closer---this revolution in thought will open new doors of possibility (I emphasize REvolution because in a way this is not new knowledge, but old knowledge articulated in another, perhaps more sophisticated way). as when going from a flat earth to a round one--- will open a new dimension of possibility will be seen available.
What is the nature of this revolution? Just as the shift in the West from a geocentric to heliocentric view was not so much finding a new idea as it was re-discovering an old one, so too is the reversal in view we are encountering today. Only in this age...instead of reversing the position of two great heavenly bodies...we are instead seeing a reversal in position of two even bigger, more general and fundamental subjects...Matter and Mind.