Twishmay

Cognitive Status of Modern Scientific Laws

// May 28th, 2010 // Philosophy

The following is an excerpt from my Philosophy presentation, part of a course I had last semester. I found it interesting enough to share over here. If you choose to read through it, please have the patience and take the time out to let it sink. It hope it is worth it.

The presentation is attached here – Cognitive Status of Scientific Laws

Introduction

“All things, from Brahma the creator down to a single blade of grass, are… simply appearances and not real.”

- Shankara, Hindu philisopher

Cognition is the process of how we percieve and experience reality. It is how we perform experiments, which are the basis for judging the best of scientific theories.

In this report, we start by discussing some problems in understanding cognition. Next we study the role of cognition in the context of quantum mechanics. Eventually we try to find out where it fits the puzzle of science.

Cognition and Reality

We experience reality through our cognitive abilities. Through these, we percieve and interact with what we term as “reality”. In our quest for the study of the natural world, our senses serve as the first stepping stone. There was a time in history when experiments did not require a lot more than sensory observation followed by rational deduction or verification of a prior hypothesis. Even when sophesticated instruments are used, the ultimate idea is to bring out a projection of some real phenomena onto a plane where we can directly observe it. We can clearly see the essential importance of cognition to the act of carrying out any experiment, which form the basis of the best of empirical or theoretical laws. Since the “goodness” of theoretical laws rests upon the correctness of the results it predicts in observable experiments, the role of the window through which we assimilate reality becomes ever more important.

Unfortunately, we do not have satisfactory theories about cognition. Our understanding of the senses is satisfactory as far as their mechanism is concerned. But how exactly do we assimilate this knowledge and view it as an individual self is a question which can only be answered by a good theory of consciousness. One such problem with cognition is that it is relative to the individial. You learn what you are taught at birth. You learn to associate “entities” that you can sense with “concepts” that are taught to you in primary school. Let us look at Fig. 1.

Figure 1

The first row of those three colors is what we are aware of. But what if a nursery child saw what is seen as the second row. His teacher had learnt it in her childhood as Red, Blue and Green and that is what she calls them. But he doesn’t see the same exact “colors”. Moreso, he still associate them with same color name, as his teacher teaches him. Thus he would still call leaves “green” and the sky “blue” as is clear by the illustrations which follow.

Figure 2 – as seen by the author

Figure 3 – as seen by the nursery child

Note that this is not an exception. Atleast we don’t have any reason to suppose so.  There is no possible way to find out if this actually happens in the case of every individual.

This was only an example, concerning the perception of color. Such a phenomenon can occur with the perception of sound or vision in general as well. We can only realize from this, the little understanding that we have of cognition and peception.

Realists vs Instrumentalists

An “Instrumentalist” subscribes to the view that in science theoretical sentences lack truth-value, that theoretical terms do not denote, and that theories are “material principles of inference” in accordance with which we move from observation to observation. Thus scientific theories are mere instruments for prediction or understanding of observable reality. The theoretical constructs themselves do not represent anything as such.

A “Realist” on the other hand holds that theories are true or false, and from this generally he draws the corollary that the elements of a confirmed theory possess “a physical reality at least on a par with the physical reality commonly ascribed to familiar objects such as sticks and stones”. Theoretical constructs for a realist represent real existing entities.

Although the realists and the instrumentalists describe scientific theories differently, it is clear that they both use scientific theories in exactly the same way, to formulate empirical laws to make predictions about the real world. Thus the role of cognition for both is equally important.

Cognition and Modern Scientific Theories

Quantum mechanics and special relativity are the two cornerstones of modern physics. Each of these two theories is applicable in its domain and provides very accurate empirical predictions. Here, we explore the role of congnition in context of quantum theory.

Quantum Mechanics

We can summarize a popular standard formulation of this theory (the Copenhagen interpretation) in terms of the following points:

1. Possible states of a system are represented as vectors in Hilbert space.
2. Observable properties are associated with linear operators which act on the vector representing the system, to give out the required property.
3. The dynamics of the system can be in two ways :
   1. Linear Dynamics: If no measurement is carried out, the system, as a superimposition of possible states, continuously evolves according to deterministic dynamics depending upon the energy properties of the system and its environment.
   2. Collapse Dynamics: If a measurement is made on the system, the system randomly acquires a particular state.

In the above formulation, 3.a. (Linear Dynamics) cannot determine whether a system will have a particular state or not, since the vector representaion is a superimposition of many states. Thus we require the Collapse Dynamics or “popping of the wave-function” to yield a particular state of the system and hence observable properties. Thus it is Collapse Dynamics which provides us with the statistical predictions which when tallied with experiments, make quantum theory a successful empirical theory. However, linear dynamics is still required to study the continuous evolution of a system which has not been measured yet.

The quantum measurement problem threatens the theory with inconsistency. What does it take for an interaction to count as a measurement? Unless we define this, we cannot we sure whether to use Linear dynamics or Collapse dynamics.  The problem in defining a measurement arises when we consider that even measuring devices are essentially physical systems interacting in usual deterministic ways and hence linear dynamics should apply to them. So what is so special about these devices as physical systems which make them alter the measured system such that it now collapses to assume a particular state? As Pauli argued, for a particle initially in a superposition of different locations,

“It is not reasonable to invent a causal mechanism according to which `looking’ fixes the position”

While the instrumentalists would say that the wave function is a mere instrument and does not represent any reality at all, Pauli the realist concluded that the collapse dynamics cannot describe a real physical process. He believed that the theory should somehow be a representation of percievable reality. Similar were the objections of Albert Einstien when he boldly stated:

“God does not play dice.”

As we can see, most of the problems that arise can be traced to the act of measurement. However, it is these very acts of measurements which are responsible for the empirical solidification of quantum theory. It explains how the sun shines, how molecules bond together, how iron is magnetized, and even why objects are hard. This is the physics that gives us computer chips, lasers, and atomic bombs. There have been alternative formulations of quantum mechanics which suggest radical metaphysical commitments concerning the nature of the physical world. The extent of such attempts can be exemplified through one such example of DeWitt’s spllitting world’s theory which explains the “popping of the wavefunction” by stating that whenever an act of measurement is carried out, the universe splits into an infinite number of parallel universes. In each unvirse, the system assumes a different state, from the given superimposition of states initially. Interestingly, surveys show that theory rates highest amongst the many variations when it comes to acceptance amongst researchers.

So why does a system assume a particular state only? Moreso, what is the reality of wave functions themselves? The only way we option observations of real phenomena is through collapse dynamics. So does a wavefunction even exist? Bohr is said to be of the opinion that in the wave function of an election there is nothing really “out there”, which means that detecting an electron at a certain position “creates” the position of this electron. The statement itself is an outrageous claim that we normally live in the delusion that there is a real objective world. Since this seems to be in blatant contradiction with both our immediate experience and everything most of us were ever taught, our natural response is to dismiss it as ludicrous.

The Important Role of Cognition

While the role of cognition in earlier scientific theories was limited to observation and experiment, quantum mechanics has made the role of cognition ever more relevant. We no more study an already existing world by carrying out some experiments. Infact, the very act of experimenting or measurement results in the creation of reality!

The measuring devices themselves are quantum systems and hence must follow deterministic Linear dynamics. So is it the very act of reading out properties from the display of these measuring devices the act of measurement which creates reality? But aren’t we humans who read these quantum systems as well? Eventually, it all comes down to that little window through which we observe the physical world. The earlier trivial discussion we had about a good theory of consciousness and cognition now is ever more relevant.

Conclusion

The realists have always assumed the world’s existance on its own. We merely interact with it and study its laws through experiment. In the context of earlier theories, this was debatable. Hoever, it seems that quantum mechanics is guiding us towards a very important realization. Under its context, the observer is extremely special. It is only when the observer pops the wave of probabilty that a dice is tossed in heaven and reality is realized.

May be we missed out on this very important detail when we set out in our quest for the ultimate physical law. What we can conclude with confidance is the fact that the scientific theories of the future would certainly take into account, this part of the puzzle which has not yet been touched upon. A theory of cognition must be a very important part of the theory of everything.

References

1. “A Historical Introduction to the Philosophy of Science” – John Loose
2. “The Emperors New Mind” – Roger Penrose
3. “Nagel on the Cognitive Status of Scientific Theories.” – Henry Byerly
4. Wikipedia (http://www.wikipedia.org/)
5. Stanford Encyclopaedia on Philosophy (http://plato.stanford.edu/)

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