Hint  Answer 
True or false? Any constant can be replaced with a variable and a quantifier to form a new wff.  
In a set of PL wffs, *this* is when there is no possible valuation of the wffs that makes them all true together.  
In a tree ~~A yields:  
Symbols followed by a variable are called what?  
The *blank* of two propositions A and B is true when A and B are both true, and is false otherwise.  
A tree in which all of the wffs have explicit truth values is called what?  
When something is true in this world.  
*This* is an individual constant or individual variable.  
In a conditional of the form 'If A then C' C is the what?  
Premise wffs do *this* to the conclusion iff there is no valuation of the atoms involved in the premises and the conclusion that makes the premises true and the conclusion false.  
What is the term for an argument with the same form of an argument with questionable validity, but is itself invalid?  
An inference step from given premises to a particular conclusion is *this* iff there is no possible situation in which the premises would be true and the conclusion false.  
If Ex appears on an open path, then we can write it as what (for any a not on the path)?  
If a tree has all closed paths, it is called what?  
When a chain of argument leads from initial premises to a final conclusion via intermediate inferential steps, which are clearly valid, we will say that the argument is *this*.  
What does wff stand for?  
When the object language is discussed, this is called *this*.  
The scope of a *blank* is likewise the wff on the construction tree where the connective is introduced.  
This describes knowing something from prior knowledge  
When premise wffs tautologically entail the conclusion, they also do *this* to the conclusion.  
~(A=B)  
No A is B translates in QL to:  
What is the name of the schema 'If A then C; not C; Therefore not A'?  
The *blank* of A is the operator introduced at the final step in the construction tree. (In QL)  
This describes something that is known without previous experience.  
Pronouns in QL are called what?  
An inference step is *this* just if, given that its premises are true, then its conclusion is absolutely guaranteed to be true as well.  
What is the object of logical studies called?  
This describes when a claim is true no matter the meanings of the English words.  
The *blank* of a quantifier in a QL wff is the subformula that starts with that quantifier.  
 Hint  Answer 
A wff A is *this* of wff B if A appears anywhere on the construction tree for B.  
Nodes in a tree are occupied by what?  
Arguments with missing premises left to be understood are called *this*.  
In a tree (A=B) yields:  
You can instantiate the A quantifier with any name that is what?  
QL trees give *what* proofs of validity?  
What is the name of the logical fallacy of the form 'If A then C; C; then A'?  
If ~Ex appears on an open path, then we can add this (with any a not already on the path).  
A set of propositions is *this* if it is logically impossible for the propositions to be true together.  
If ~Ax appears on a path, it can be written as what (if c is a variable already on the path)?  
A wff is a *blank* if it takes the value false on every valuation of its atoms.  
In a tree ~(A^B) yields:  
All A are B translates in QL to:  
Some A is/are B translates in QL to:  
When the object language expresses various claims, this is called *this*.  
When can two quantifiers be switched around?  
What is the term for the logical fallacy when you change the quantifier of the derived premise?  
The PL wffs A and B are *this* just if, on each valuation of all the atoms occurring in them, A and B take the same value.  
An argument is *this* just if it has all true premises and the inference from those premises to the conclusion is valid.  
If a tree has an open path it is called what?  
When using a rule to strip off a quantifier, the resulting wff is called a *blank* of that quantified sentence.  
In Propositional Logic (PL), what do the letters P, Q, R, and S stand for?  
You can instantiate the E quantifier with any name that is what?  
This describes when a claim is true in the meaning of the words.  
If a path contains a pair of wffs of the form W, ~W, then the path is *blank*.  
What is the name of the schema 'If A then C; A; Therefore C'?  
When something must be true in all possible worlds.  
A kind of extrapolation from the past to the future, or more generally from old cases to new cases, is called *this*.  
A set of propositions is *this* if it is logically possible for the propositions all to be true together.  
When an inference is deductively valid, we'll say that the premises do *this* to the conclusion.  
 Hint  Answer 
What means roughly everyone/everything x is such that ...?  
A wff that isn't closed is called?  
A skeletal pattern of an argument is *this*.  
A wff of PL is a *blank* if it takes the value true on every valuation of its atoms.  
If Ax appears on a path, we can add what (if variable c is already on the path)?  
What is the language in which we conduct the investigation of and discuss what is going on in the objectlanguage?  
In a tree ~(AvB) yields:  
An occurrence of a variable x in a wff A is *this* iff it is in the scope of some matching quantifier that occurs in A.  
A way of forming a complex sentence is *this* if fixing the truthvalues of the constituent sentences of the complex sentence is always enough to determine the truthvalue.  
An atomic wff of QL is formed from a nplace *blank* followed by n *blank*  
In a tree (A > B) yields:  
The *blank* of two propositions A and B is true when at least one of A and B is true, and is false otherwise.  
In a tree (A^B) yields:  
*These* are arguments containing a premise that isn't used in getting to the conclusion.  
The *blank* of a proposition A is is true when A is false and is false exactly when A is true.  
If ~Ex appears on an open path, then we can exchange it with what (using a, a new variable)?  
The *blank* of two propositions A and B is true when exactly one of A and B is true, and is false otherwise.  
The *blank* of a nonatomic wff is the connective that is introduce at the final stage of its construction tree.  
An occurrence of a variable x in a wff A is *this* iff it is not bound.  
What means roughly someone/something x is such that ...?  
If a path does not contain a pair of wffs of the form W, ~W then the path is *blank*.  
The *blank* of a connective in A is the wff on A's construction tree where the connective is introduced.  
A *blank* of QL is a wff with no free occurrences of variables.  
In a tree ~(A > B) yields:  
What states that an inference with actually true premises and an actually false conclusion can't be deductively valid?  
A set of PL wffs is *this* if there is at least one possible valuation of the relevant atoms which makes the wffs all true together.  
In a tree (AvB) yields:  
A tree in which all of the wffs do not have truth values assigned because they are all assumed to be true is called what?  
In a conditional of the form 'If A then C' A is the what?  
Positions on a tree are conventionally called what?  

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