I think all of us here can agree that seeking to describe our universe in terms of laws and principles that allow us to make predictions about its dynamics is a worthy and fascinating pursuit. It is also undeniably valuable to any species that wishes to live and thrive in it.
However, us humans have developed this need to explain everything in terms of reasons for why things happen. What that means, exactly, varies between different contexts, but some interpretations are
- reasoned (practical or theoretic) justifications for actions taken by an agent;
- (primary) causes of events (“which of recent events was most necessary for this event to occur?”);
- teleological purposes attributed to objects or events which explains their behaviours or occurrences (e.g. involving attractors in complex adaptive systems);
- sets of rules (dynamics) governing the evolution of systems which demonstrably gives rise to observed phenomena - the type of reasons most physicists are primarily concerned with.
There are a lot of finer distinctions to make - this was mostly off the top of my head. The point is: given any reason at all, one can always additionally demand a reason for that reason - but at which level in this hierarchy of explanations would you find the final, most fundamental and satisfactory explanation for why anything at all? Could such a level exist, or is the hierarchy infinite? Is the notion of what constitutes a ‘reason’ fundamentally anthropic, and is then requiring explanations for natural events a case of category error?
tl;dr: why, when and where is 42?
My take is that any logical reasoning requires some axiom or assumption at its base which is not justified. Then we can apply that reasoning to cases where we believe that assumption applies.
In physics, we work from a set of assumptions about the nature of reality which are not justified by anything but empirical observation. The application of empirical observation and the scientific method in general is not justified by anything other than the historical success in its application (famously “it works, bitches”).
These are not stringent justifications, but practical.
If there is anything we can be sure of, it’s that we perceive ourselves as existing. That makes empirical observation the best, and only, sanity-check.