I am reading the book An Introduction to Formal Logic by Peter Smith. I was checking the following argument (Exercise-1 Question no-15) :
Miracles cannot happen. Why? Because, by definition, a miracle is an event incompatible with the laws of nature. And everything that happens is always consistent with the laws of nature.
Now, the author has written the following in the answer sheet:
Invalid. The premisses tell us that in fact no miracle ever happens. But they don’t tell us that miracles cannot happen. Compare:
Crimes cannot happen. Since, by deﬁnition, a crime is an act incompatible with the criminal law. And everything that happens is always consistent with the criminal law.
In a law-abiding community the premisses may be true: it doesn’t follow that criminal activity is impossible!
The author and some people seem to stress that 'And everything that happens is always consistent with laws of nature' means everything that has happened or is happening is consistent with laws of nature. It doesn't eliminate the possibility that anything can happen in future which is incompatible with the laws of Nature.
Similarly, they want to stress that 'No miracle ever happens' doesn't eliminate the possibility that it can happen in future. However, 'Miracle cannot happen' is the statement that eliminates that possibility. The same thing can be said about the second argument.
Now, Is the author making the right point? I mean we have other such simple present sentences:
- Two plus two equals four.
- Sun rises in the East.
- Forces occur in pair.
Now, are these sentences claiming only about past and present but not about future? How should we interpret these simple present sentences?
P.S- I have also posted this question on Mathematics Stack exchange for those of you interested.