Feynman has expressed his opinion on this in one of the Messenger lectures on the Character of Physical Law that he gave at Cornell.
This is an example of the wide range of beautiful ways of
describing nature. When people say that nature must have
causality, you can use Newton's law; or if they say that
nature must be stated in terms of a minimum principle,
you talk about it this last way; or if they insist that nature must have a local field - sure, you can do that. The question is: which one is right? If these various alternatives are not exactly equivalent mathematically, if for certain ones there will be different consequences than for others, then all we
have to do is to experiment to find out which way nature
actually chooses to do it. People may come along and argue
philosophically that they like one better than another; but
we have learned from such experience that all philosophical
intuitions about what nature is going to do fail. One just
has to work out all the possibilities, and try all the alternatives. But in the particular case I am talking about the
theories are exactly equivalent. Mathematically each of the
three different formulations, Newton's law, the local field
method and the minimum principle, gives exactly the same
consequences. What do we do then? You will read in all
the books that we cannot decide scientifically on one or the
other. That is true. They are equivalent scientifically. It is impossible to make a decision, because there is no experimental way to distinguish between them if all the consequences are the same. But psychologically they are very
different in two ways. First, philosophically you like them
or do not like them; and training is the only way to beat
that disease. Second, psychologically they are different
because they are completely unequivalent when you are
trying to guess new laws.