Occasionally I come across ideas so profoundly shocking, that I would simply reject them as being batshit craziness, except that due to their rigorously scientific, falsifiable nature, and due to the academic reputation of the researchers involved, I can't. Perhaps the most intuitively "obvious" notion that most people possess is that time flows from past to future. The arrow of causality inexorably flows in one direction only: From past to future.
The April 2010 edition of Discover magazine contains an article summarizing what may be among the most profound research ever undertaken into the ultimate nature of reality. Entitled: "Back From the Future" the article summarizes recent research in quantum physics which appears to demonstrate conclusively that the future influences the past. The arrow of causality points BOTH directions: from past to future AND from future to past! [i] [ii] [iii]
On considering this possibility, I do believe that the long established principle of quantum entanglement, most probably entails this dual arrow of causality. Experiments have demonstrated that when two or more elementary particles such as photons become entangled, any change to one particle, such as measuring its previously undetermined spin, causes an instant corresponding change in this property for the other particle--even if they were separated by light years. This effect propagates far faster than the speed of light. It appears to propagate instantaneously across any distance. Entanglement is telling us something deep and fundamental about the nature of our universe--but what? The answer seems to be that time and space are not the absolutes which they appear to us to be.
In retrospect, this really is not too surprising. The universe is unimaginably vast and complex. Living organisms, existing in a given location, at a particular moment in time, need to, quite literally, focus only on that small restricted subset of all information which imparts immediate survival value to them.
Sight is obvious. The Earth's atmosphere is transparent to solar radiation--light--at one narrow bandwidth:
Hearing is also obvious. Given the density of our atmosphere, motion in it will produce compression and expansion of the local atmosphere--"sound". This can provide a great deal of information about our environment. Molecules will float in this atmosphere. Detecting them tells us about whatever emitted them. Is it something we might wish to eat--or is it something which might wish to eat us? Thus smell and its closely related sense of taste have survival value. Similarly with the sense of touch which allows us to be aware of whatever is directly interacting with our bodies.
With these senses, living organisms create a "lifeworld" containing survival relevant information. Within this lifeworld, simple notions of causality possess great survival value: "If I climb the tree BEFORE the bear--which I see, hear and smell, and so reasonably can assume is there--gets here, I will not get eaten, otherwise, I will get eaten" When it comes to survival, timing is everything. I once expressed this idea as a poem:
All that we unquestioningly think that we know,
does ultimately, from five fallible senses grow,
our reality is thus naught but a fragile web, wrought,
of disparate strands woven together, like as not,
with chords of reflexive, unreasoned, presumption,
so that, that which we upon first thought,
believe to be so, is only Mind's tentative assumption.