Every sentence (or rather, proposition) is both true and false, since “false” is defined here to mean having a true negation (and all negations are established as being true.) So for P to be both true and false would be for both P and ~P to be true, or, deflatively, for it to obtain that P and ~P.
If (alternatively) neither P nor ~P—as might sometimes be the case according to intuitionists—we would say that P is neither true nor false.
Every sentence (or rather, proposition) is both true and false, since “false” is defined here to mean having a true negation (and all negations are established as being true.)
If false is defined as the property of having a true negation, than under trivialism there’s no real semantic distinction between true and false, since there’s no property that can distinguish between the set of true and false propositions. This is of course to be expected, but I was curious if trivialism could be interpreted as a system that poses significant distinctions of truth values: for example, one that postulates that some propositions can be true and false, but not necessarily all of them: some of them could just plainly be true. I know that such a system can be formally coherent (after all, there is one that is isomorphic to classical logic), but I’m interested if it has been used in that way.
If (alternatively) neither P nor ~P—as might sometimes be the case according to intuitionists—we would say that P is neither true nor false.
I was curious if trivialism could be interpreted as a system that poses significant distinctions of truth values: for example, one that postulates that some propositions can be true and false, but not necessarily all of them: some of them could just plainly be true. I know that such a system can be formally coherent (after all, there is one that is isomorphic to classical logic), but I’m interested if it has been used in that way.
In that case it’s not trivialism anymore, but there are nonclassical logics where some (but not all) propositions are true and false; indeed such things are considerably more popular than trivialism (for what I presume to be obvious reasons.) Graham Priest, for instance, is constantly pointing out that if you drop the principle of explosion it’s very easy to have the Liar’s Paradox be simultaneously true and false without implying that Socrates simultaneously is and isn’t mortal.
Does anyone know if trivialism has to be interpreted as “every sentence is at least true” or as “every sentence is true and only true”?
Both.
Every sentence (or rather, proposition) is both true and false, since “false” is defined here to mean having a true negation (and all negations are established as being true.) So for P to be both true and false would be for both P and ~P to be true, or, deflatively, for it to obtain that P and ~P.
If (alternatively) neither P nor ~P—as might sometimes be the case according to intuitionists—we would say that P is neither true nor false.
If false is defined as the property of having a true negation, than under trivialism there’s no real semantic distinction between true and false, since there’s no property that can distinguish between the set of true and false propositions. This is of course to be expected, but I was curious if trivialism could be interpreted as a system that poses significant distinctions of truth values: for example, one that postulates that some propositions can be true and false, but not necessarily all of them: some of them could just plainly be true.
I know that such a system can be formally coherent (after all, there is one that is isomorphic to classical logic), but I’m interested if it has been used in that way.
But this, I get, is not trivialism.
In that case it’s not trivialism anymore, but there are nonclassical logics where some (but not all) propositions are true and false; indeed such things are considerably more popular than trivialism (for what I presume to be obvious reasons.) Graham Priest, for instance, is constantly pointing out that if you drop the principle of explosion it’s very easy to have the Liar’s Paradox be simultaneously true and false without implying that Socrates simultaneously is and isn’t mortal.
You get correctly, yes.