... except that it isn’t.
Wikipedia says that ‘A valid logical argument is one in which the conclusions follow from its premises’?
And that is not at all how we are thinking about logical validity on this course.
Why does Wikipedia say that ‘A valid logical argument is one in which the conclusions follow from its premises’?
Let me put it like this.
On this course our aim is to get a handle on formal logic.
To this end we start with some stipulations about logical validity
and related notions that almost everyone agrees are roughly right and
These stipulations enable us to get a handle on formal logic while
avoiding some interesting philosophical controversies about
what logic is.
This makes sense: you can’t really do philosophy of logic without
any sense of what logic is.
But once you’ve understood something about formal logic, you can go on
to think more critically about logical validity.
Logic is the study of logical validity, and what we are learning is logic.
If you end up in a position to criticise our defintions of logical validity,
it will be on the basis of your understanding of what logic is.