“An idea, like a ghost, must be spoken to a little before it will explain itself” – Charles Dickens
One popular and perfectly understandable misconception that has resulted from all the metaphysical talk spewing from physicists these days is the notion that time does not exist. Very few physicists have actually suggested this. You’ve got to love the ones that have since it gives you a great reason not to go to work in the morning, because after all I went to work yesterday, and if time doesn’t exist then effectively I already went to work tomorrow too. Take advantage of this, but make sure that you find the nearest physicist and give him a big, wet kiss for his service to the common man. Now, let’s agree on a few things first. Time is not an illusion. Oh, keep your chakras aligned. I know that there are philosophical perspectives out there that use that sort of phraseology, but the point most are trying to make is that time is unimportant, rather than non-existent. Live for today. Be good today. Experience today. Secondarily, the universe is not an amorphous glob of everything happening simultaneously. If this was true, I could claim to have never left the ladies unsatisfied. I regard this as extremely unlikely (as do the ladies) to the extent of completely invalidating the possibility, both practically and probabilistically. Thirdly, and most important for our purposes is that while the “arrow of time”, that is the way in which time moves, is normally apprehended by our conscious mind as only moving forward into the future, there is absolutely no necessity for this as the laws of physics appear to be essentially “time reversible”. This is to say, the universe could be played backwards and not only would it tell you that “Paul is dead” and to worship the devil, but the laws of physics still make sense. The math works. The math also screws you out of a good interest rate, raises your insurance premiums, and if the figures are high enough runs away with your wife, so you really can’t always trust the math. We’re very comfortable chopping time up into discrete units of nanoseconds or millennia, as it helps us figure out when to feed the dog, go to the job interview, or start a land war in Asia. Since you’ve read this far, hopefully you’ve at least provisionally agreed that time exists and seems to move perceptibly forward. If you haven’t, odds are you finished reading this before you started, so no spoilers please. Our perception of time, on the other hand, is somewhat more malleable, and you are perfectly capable of finding “infinity in the palms of your hand and eternity in an hour”, as the poet William Blake mused, which begs the question of even if time exists, need it be contiguous (in the sense of being in direct contact with something)? And if time is not fundamentally contiguous, might this offer an explanation for our annoyingly persistent tendency to see ghosts?
So, let’s proceed from the hypothesis that time does indeed exist in some fashion and generally moves in one direction, but is not indisputably contiguous, rather that last second proceeded this second, but that it is not a requirement that the two seconds be immediately adjacent. Certainly, for our convenience we can slice and dice time into miniscule parts, but there isn’t any consensus out there that time can ever ultimately be quantized, or has some sort of light-like wave-particle duality, or alternatively is some sort of continuum that flows past or with us. Thus, if it’s at least theoretically possible that time is discontiguous (not illusion, moving in one direction, but not in discrete, yet connected units), what would the spaces in between discontiguous moments in time look like to us dedicated followers of contiguous time with highly adjustable mental faculties for perceiving the passage of time? I feel an overwhelming compulsion to say “Kanye West”. I don’t know why. Well, now that’s out of my system, the truth is to conceive of what the perception, were it possible, of discontiguous time might look like to our mammalian brains, we need a solid metaphor. Metaphors are important. They’re soft and fuzzy. They teach the kids literary responsibility. Everybody should get one. Personally, I like radar.
Radar is cool. The basic idea is to bounce radio wave pulses off of objects. If there happens to be something reflective in the way (say like a nice solid airplane), a small fraction of the wave is bounced back to the receiver, and variations in the information that returns can tell you about altitude, speed, bearing, and distance. We’ve all seen the classic spinning radar dish (which is now relatively obsolete with more sophisticated non-spinning phased arrays), but you turn the radar so that you know what direction to look for your target. If you simply sent out radio waves in all directions, you would know something was there, but you wouldn’t know what direction it was coming at you from. Think of the human head as stationary radar. You might smell something suspicious nearby, but you have to turn your head and take in more data to pinpoint where the offending odor is originating, unless there is a toddler or unidentified pile of nastiness directly in front of you. With radar, you transmit your pulse, but have to wait for the wave to return, the amount of time this takes pinpoints the distance (transmit/receive is toggled back and forth at a predetermined rate), meanwhile your dish keeps spinning, and eventually hits the same target again, and you can get even more information by the changes in how it now reflects your pulse. You see an object. Then you see an object again, but even with advanced signal processing, you are seeing a contact at two discontinguous moments in time. This is not so troublesome when you want to launch a missile at something because given the two positions of your object, you can make a pretty good prediction where it’s going to be next, but because your successive detections are separated in time (the amount of time to transmit and receive the reflection), technically anything could have happened in the moments between detection at point A and point B. Human senses, in a similar fashion, do not apprehend the universe instantaneously. We receive sensory input, and then we look again, and receive more sensory input. This is all smoothed out by our friendly brains, but from the time when we first apprehend stimuli, to our registering that second apprehension there is a gap. Hence it’s a bird. It’s a plane. Oh, now I see, it’s Superman. It is the interstice between moments that concerns me, what we would desire to call an “intervening moment”, which we would like to think has some independent existence, or is in fact just an unobserved element of time, but if ultimately we cannot quantize time (and given this is just one among many theories), then we have no idea what that space in between moments actually represents, except that we unnecessarily understand it as continuity in time, whereas we cannot prove that the preceding moment is immediately adjacent to this moment.
Since we’re stringing out a rather tenuous metaphor surrounding ghosts and radar, it should come as no surprise that the phenomenon of “radar ghosts” has some bearing. When you bounce a radio pulse off a moving object you can sometimes get clutter from what are called multipath echoes, that is the ground or atmosphere can produce anomalous propagation of the return signal resulting in “ghosts” that while tangentially related to the target, are not the target itself. Effectively, they are perceived by the detection apparatus, but do not otherwise exist. What if time behaves similarly? What if, as we perceive a moment of reality, we might also under the appropriate circumstances, perceive the clutter within the space between, the radar ghosts of our senses, reflecting our sensory awareness of surrounding moments in time, bounce-back from moments before and moments after that reside in the discontinuity? What would we see? If time is indeed discontiguous, our “clutter” would amount to the detection of thing that may have happened before or after. Ghosts of the past and ghosts of the future. Of course, one must ask what problems this solves? Consider the fact that our awareness of ghosts more often than not is tied to a specific place. Ghost armies march on battlefields where they fought. Murder victims haunt the houses where they died. Thus, perhaps we apprehend a kind of interference, a “radar ghost” of our target (our target being the eternal “now”). We feel we are moving in time, but what really happens from one moment to the next, or more succinctly, what happens in the moments that are not moments between the moments that are eludes us, and does the fact that we move inexorably forward in time prevents us from perceiving what has or will happen, for as Ashim Shanker observed, “the arrow of time obscures memory of both past and future circumstance with innumerable fallacies, the least trivial of which is perception.”
We can’t prove time exists independently of changes within the universe or our local frame of reference. Time itself is a very useful abstraction, like the ideas of zero, mathematical equality, or infinity – like a straight line, these are never found in nature. We measure time by supposedly equal cycles of change, beginning with the day and the year for the ancients, all the way up to the light emitted by the cesium atom in defining the second for scientists. There may be a case for discontiguous time if we can discover discontiguous events or changes within our environment, even at the quantum level.
Like time, space is another useful abstraction, which can’t be proven to exist independently of physical objects. We measure “space” between objects with a rod composed of equal distances to obtain the total distance between objects. Both time and space are always relative, perhaps implying the universe itself is only relative, not infinite according to some theories.