Please do 37,38,39,40 only (please do it the way i solved one of the problems)

Philosophy (introduction to formal logic)

These questions need to be proven by models where you use universal discourse, extension and refs

For example, for Pa---> ~Qb

You need to do write (contingent) first the prove like this

false true

UD={Jack, Bob} UD={Jack, Bob}

Ext (P)={Jack} Ext (P)=0

Ext (Q)={Bob} Ext (Q)=0

Ref (a)=Jack Ref (a)=Jack

Ref (b)= Bob Ref (b)=Bob

Directions Determine whether the following arguments are valid. Show your work with models Directions Determine whether the following arguments are valid. Show your work with models