In Part — I it was mentioned that accepting the tenet of ‘realism’ means believing in the existence  of things ‘from their own side’ independent of consciousness. By briefly discussing the Newtonian  idea of ‘gravitational influence distant objects have on each other’, it was pointed out that Einstein  regarded such an action-at-a-distance as ‘spooky’ — if an object’s gravitational field is taken to be  affecting another distant object instantaneously. Finally it was remarked that Einstein preferred to  consider reality as ‘local’, rather than ‘spooky’.  

The ‘spookiness’ of interaction was taken as implying a ‘cause’ leading to an ‘effect’  INSTANTANEOUSLY, whereas, the ‘local-ness’ of interaction requires a ‘cause’ to PRECEDE the  ‘effect’ (and, there’s more to this ‘PRECEDING’, as discussed below).  

All these considerations imply that the tenet of ‘realism’ has TWO main aspects:  

The first one is — its basic meaning (as discussed in Part — I): Belief in the existence of things  ‘from their own side’ independent of whether we look at them (or sense their existence through by  other means) — for example, I know that my coffee mug exists independent of me ‘looking’ at it and  I believe in the existence of that mug from its own side. 

The second one is — the question of adding an adjective (spooky or local) to the term ‘realism’:  Deciding whether the reality (the physical existence) of my mug is ‘spooky’ or ‘local’. For example,  does my belief in the mug’s existence involve any cause-effect relation?  

Let’s address this query by first asking what it could mean to say that the reality of the coffee mug is  ‘spooky’: Spooky realism of the coffee mug would imply that, we ‘see’ the mug at the very instant we  ‘look’ at it!  

You’ll ask — isn’t it correct that I ‘see’ the mug at the instant I ‘look’ at it?  

A careful consideration would imply that this is not true: It takes time for the process to occur —  from ‘looking at something’ to ‘seeing it’ — it’s not instantaneous!  

There is nothing spooky about the existence of coffee mug. Let’s see how:  

Apart from the field of ‘gravity’, there is another ‘field’ that we come across in our daily life.  Working — of all our remote controls and microwave ovens and mobiles and wi-fi networks and  GPS systems and satellite TV channels and many more applications — involves it. It is the  ‘electromagnetic (EM) field’.  

Light, being a form of an EM field, can propagate even in vacuum, covering a distance of about  three hundred-thousand kilometres in just one second. (Light is the ‘visible’ part of the  electromagnetic spectrum).  

Briefly speaking, our ability of ‘seeing’ a particular object from a distance involves ‘reflection of  light’ from that object [the ‘cause’], ‘propagation of that light’ to the eye, forming its image in the  eye, followed by the processing of that image in our brain [the ‘effect’].  

So when you say: “I can SEE a coffee mug about a metre away from me there on the table NOW”,  Einstein modifies your statement and says: “Indeed you SEE that coffee mug NOW, but you see it  AS IT WAS about a one-third of ten nanoseconds back!”  

In Einsteinian Physics, the ‘local-ness’ of interaction with respect to a given frame of reference  means satisfaction of TWO conditions:  

The first one requires the ‘cause’ to PRECEDE the ‘effect’.  

The second one states that the event of ‘cause’ at one place can lead to an event as its ‘effect’ at  another place only if the time between their occurrences is NOT LESSER THAN the time  required by light to propagate from the ‘cause’ event to the ‘effect’ event.  

Combining these conditions with the basic idea behind realism means referring to the tenet of  ‘Local Realism’. The reality of the coffee mug is very much ‘local’ in this sense!  

Thus, Einsteinian Physics — based on the tenet of Local Realism — puts an upper limit on how fast  the occurrence of one event (happening before — in our example: ‘looking at the mug’) can affect  the occurrence of some other event (happening after — in our example: ‘seeing the mug’).  Independent of any particular reference frame, this upper limit is given by the ‘speed of light’. It  fundamentally changes our view about reality. Specifically, it leads to the abandonment of the  (Galilean-Newtonian) notions of ‘absolute time’ and ‘simultaneity’.  

Exploration continues… 


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