Georgina,
Thank you for your very kind and thoughtful comments. We agree on many of the fundamental attitudes. I will try to address questions that you raised ...
You write,
"...[Planck's Law] is not a Law of the Universe..."
That is a key distinction that I believe needs discussion. Yes, I do say that my derivation of Planck's Law shows that this Law is not some 'Universal Law of Physics', but rather a mathematical statement, a truism in fact! I go even further, however, and argue that ALL laws of physics should be likewise.
My basic view is that 'before manifestation there is accumulation' of energy. I have many and varied reasons for saying this. We experience this in everyday lives and in so many ways. It is 'sensible' and so 'makes sense' . Planck's constant h is the minimal accumulation of energy that can be manifested. But I further argue in my essay that the existence of h is due to our theoretical regime. That in a sense our definitions of energy and temperature, etc., and the theory we weave from these become like a 'conceptual lens' through which we 'see' Nature. And that 'conceptual lens' has a build in 'focal point' beyond which we cannot go. That 'focal point' is Planck's constant! It has nothing to do with the Universe!
You say,
"... I am not persuaded that it is time that gives objects physical existence ..."
There are many ways of conceptually understanding time. Certainly, time as an ordering parameter of the occurrence of events is not what I have in mind. This gets a little tricky to make clear in a comment. But try to understand my statement about 'time and existence' in the context of everyday life and not exclusively as it is used in Physics. What I have in mind is not 'time' as a parameter to sequence events, but rather as 'duration' of an event. Such 'duration of time' results from the 'entity' being in 'equilibrium' with the 'environment'. As long as that 'equilibrium' is maintained, the 'entity' exists.
Since we are talking about 'time', I should share with you recent insights I have on this key distinction: time as 'duration' and time as 'instantiation' (ordering parameter). I mathematically demonstrate in the essay that Thermodynamics asserts that 'any physical process (event) takes some positive duration of time to occur'. However, physical events in GR are described by (x,y,z,t) with time in the sense of 'instantiation', t=s. In my opinion, this violates Thermodynamics. 'Dark energy' and 'inflation' seek to correct for this flaw!
You further say,
"...you are saying that physics is a man-made construct like history, culture and politics and not God given or written in the Universe."
Certainly, any think created by man is man-made. I don't believe in God-given Universal Laws. To my philosophic sensibilities, this is just absurd! But I like to say something more regarding all this. Creation follows the same processes, whether it is in History, or Politics or personal lives or Physics. This is plainly so, since all of these activities is what WE do as human beings! I find I get clearer understanding of Physics thinking about Politics!
Constantinos