How is this related to the failure of String Theories and what's the connection to Inflationary Theory?
As I understand it, the choice of which units/scales are simply a matter of convenience and whilst measuring length in terms of Planck lengths may be appealing scientifically, it's unlikely to gain much usage outside of scientific circles due to the non-human scale numbers used. Of course we could adapt to using e.g. 1.0e35 Planck lengths instead of approx 1.62m but why bother.
The point of article is not just to debate English translation of Planck's original paper, but to also point out that there is nothing "fundamental" about Planck's scales in any known experimental physics - ie Planck's length isn't the dimension of one pixel of universal reality, or movement.
In all String Theories "the characteristic length scale of strings is assumed to be on the order of the Planck length, or 10−35 meters, the scale at which the effects of quantum gravity are believed to become significant."
In Inflationary cosmology, the unit of expansion is Planck's time scale, and is needed to justify existence of negative gravitational pull (repulsive force).
If as the author argues, Planck scales are merely "defining" renormalization constants and don't represent anything physically "fundamental" in experimental physics, then both of these theories lose their foundational connection to reality, even theoretically speaking, let alone any experimental evidence.
>"the characteristic length scale of strings is assumed to be on the order of the Planck length, or 10−35 meters, the scale at which the effects of quantum gravity are believed to become significant."
Does it matter for the theory that it has to be exactly at (the currently defined) Planck length, and that if it's anything else the theory breaks down? What about simply "that order of magnitude"?
As I understand it, the choice of which units/scales are simply a matter of convenience and whilst measuring length in terms of Planck lengths may be appealing scientifically, it's unlikely to gain much usage outside of scientific circles due to the non-human scale numbers used. Of course we could adapt to using e.g. 1.0e35 Planck lengths instead of approx 1.62m but why bother.