Please demonstrate how it is valid
I get the impression that either you have not done any schoolwork in elementary logic, or you have forgotten it.
Some important things to note:
1) Valid arguments very often contain the word "if". A classical example might be, "If X is a man, then X is mortal. Socrates is a man; therefore Socrates is mortal." Any time you have a statement "If P, then Q," alongside the statement "P", and you conclude "Q", you are doing what is called
affirming the antecedent, or applying
modus ponens.
2) An argument is called
valid if any time the premises are true, the conclusion must also be true.
In part 1 of my argument, I present a statement in the form, "If P and Q, then R." I then assume P; Q is not controversial; I thus conclude R.
Similarly, the response, "If I was faithful to you, then Samantha was lying," is a true statement.
I would like to reiterate my statement that the conspiracy is entailled by the flatness of the Earth but is nowhere used as evidence for the flatness.