Letter To A Physicist

 

This letter was an answer to a physicist who asserted that science has priority, not philosophy.

        There is ’science’ then there is the ’scientific method’; you do not seem to acknowledge their differences. Knowledge, prediction (even if mathematical) is science as much as philosophy is science. The philosophical a priori that one need to do ’science=knowledge’ can make all the difference in how I view the usefulness or nature of the ’scientific method’, a method based on logic, therefore philosophy.

For example, if I assume philosophically (you might say scientifically, having your experimental goal in mind) that ’all there is’ is, or can be, mathematically accessible or understandable. That assumption is a philosophical one, not a scientific one.

The Scientific Method measures and counts, If I assume that all I care and worry about can be measured and counted so far so good. We are all witnesses to how far that Scientific Method has taken us.

I do not for an instant doubt or question the utility, the grandeur of the Scientific Method. Far from me the thought. But in the realm of Knowledge (Science if you will) it is only part of the story.

In the realm of Knowledge science is limited

How does the Scientific Method fares with the following:

The universe itself cannot be subjected to physical experimentation. The universe cannot be observationally compared with other universes.

         Establishing a Robertson-Walker geometry for the universe relies on plausible philosophic assumptions. The deduction of spatial homogeneity follows not directly from astronomical data but because we add to the observations a philosophical principle that is plausible but untestable. George F. C. Ellis refers to the notion that the universe is isotropic and homogeneous (on a large scale). From our vantage point, we can see that the CBR (cosmic background radiation) yields this result; but to show that the inference is valid for the universe as a whole, we would need to make the same observation from at least two other (far removed) vantage points. However, if the Copernican Principle is invoked that we do not occupy a special place in the universe (this is the philosophic principle Ellis refers to ), then what we see is equivalent to what would be seen from other positions, and the homogeneity and isotropy is demonstrated.

The Physics Horizon limits our knowledge of physics relevant to the very early universe. We cannot experimentally test much of the physics that is important in the very early universe because we cannot attain the required energies in accelerators on Earth. We have to extrapolate from known physics to the unknown and then test the implications; to do this, we assume some specific features of known lower energy physics are the true key to how things are at higher energies. We cannot experimentally test if we have got it right.

Ellis sets forth the following criteria for a good scientific theory:

1. Satisfactory structure: a) internal consistency, b) simplicity (Ockham’s razor), and c) aesthetic appeal (’beauty’or ’elegance’)

2. Intrinsic explanatory power: a) logical tightness, b) scope of the theory—the ability to unify otherwise separate phenomena, and c) probability of the theory or model with respect to some well-defined measure.

3. Extrinsic explanatory power, or relatedness: a) connectedness to the rest of science, b) extendability. providinga basis for further development;

4. Observational and experimental support, in terms of a) testability: the ability to make quantitative as well as qualitative predictions that can be tested; and b) confirmation: the extent to which the theory is supported by such tests as have been made.” 

The last criterion in my view (and that of many scientists and philosophers of science) is critical. If a theory cannot in principle be confirmed quantitatively it is not science, but belongs to other disciplines.

The basic underlying cosmological questions are:

1. Why do the laws of physics have the form they do? Issues arise such as what makes particular laws work? for example, what governs the behaviour of a proton, the pull of gravity?...

2. Why do boundary conditions have the form they do? (Note: I would inject here Roger Penrose’s speculation as to why the initial region from which the universe grew was so uniform, that is, whence the Second Law)..

3. Why do laws of physics at all exist? This relates to unsolved issues concerning the nature of the laws of physics:

are they descriptive or prescriptive? ...Is the nature of matter really mathematically based in some sense, or does it just happen that its behaviour can be described in a mathematical way?

4. Why does anything exist? This profound existential question is a mystery whatever approach we take.

5. Why does the universe allow the existence of intelligent life? This is of somewhat different character than the others and largely rests on them but is important enough to generate considerable debate in its own right.

The status of all these questions is philosophical rather than scientific, for they cannot be resolved purely scientifically.

How many of them—if any—should we consider in our construction of and assessments of cosmological theories?”