Tuesday, January 17, 2006


"Logic has fallen into severe disfavor and people are quite startled when they are confronted with it." - Rebecca Merrill Groothuis


Joseph Hinman (Metacrock) said...

Fine quote. Never more true than in dealing wiht athesits on message boards. I hope it is more than just my self appointed task to deal with them, but I do deal with them a lot. It seems modern atheists are a cult of "objective empirical data;" for many that is their only standard. Some even repuidate logic altogether thinking all we need is empiricism.

When accuse them of oppossing the law of non contradiction they often become unrulie.

Tom Gilson said...

Metacrock, I agree, and to take it further I'm wondering what empiricism looks like without logic. I think it's most likely to be, "I see what I want to see and conclude what I want to conclude." Is that an unfair analysis?

Susan said...

I am currently reading "Testing Christianity's Truth Claims" by Gordon Lewis. Chapters two and three outline the views of two apologists who are logical, rational, and also empiricists. Without the rules of logic, what would one use to examine empirical data? I suppose, Tom, your analysis is not unfair!

Anonymous said...

I wonder too, if the issue at hand, is perhaps more basic yet. By this I mean, are there not philosophical/theological presuppositions that drive the logical argument? While the proper and consistent use of logic is important, for discussion sake, without quickly moving to the underlying assumptions, are we not granting human autonomy a place it should not have?

John Stockwell said...

Logic is best studied in the context of mathematics. What passes for "logic" in the world of the theologian is a metaphysically laden sham.

Santos said...

John S.

That is an interesting assertion. Care to share the logic of your conclusion?

John Stockwell said...

Sure. The sort of thing we see coming out of theology, and many other classical philosophical endeavors, employs Aristotelian-style syllogisms, which usually consist of statements elements that are heavily laden with metaphysical assumptions.
These elements likely have an ambiguous truth value, making it dubious that such statements are well formed formulas in the first place. What results is a sort of pseudo-logic that has the form of logical statements but which are neither true nor false.

Susan said...

John -- you seem to suggest that when a person begins with, for example, "12" as the first statement in a proposition, that person has begun with a brute fact. No need to prove 12 is true, or real. 12 is just 12 and everybody accepts it. Whereas any other proposition, one that uses words rather than numbers to communicate its assertion, is inherently dubious? Is this what you imply, John?

John Stockwell said...

The requirement for forming a well formed formula in logic is that the statements are objects with definite truth values.

If a person is making a so-called logical argument consisting of statements of ambiguous or questionable truth value, and seeks to be convince someone else merely on the grounds that the argument is believable because the argument is "logical", then that person is engaging in a act of misdirection.

Santos said...

John S.

Logic has to do with the flow of thought and not only the validity of the assumptions. Consider the following paragraph

"If I believe that whales are mammals and that all mammals are fish, then it would also make sense for me to believe that whales are fish. Even someone who (rightly!) disagreed with my understanding of biological taxonomy could appreciate the consistent, reasonable way in which I used my mistaken beliefs as the foundation upon which to establish a new one"

My point is that although truth rests on valid assumptions the logic of the argument does not.

For example, if I convert your argument in a syllogism it would look something like this:

Premise 1: True logic does not allow metaphysical assumptions.

Premise 2: Theology relies on metaphysical assumptions.

Conclusion: Theology does not follow true logic.

I passionately disagree with your premises and thus with the validity of your conclusion. But I see your logic!

Susan said...


Your own propositions seem wanting as "objects with definite truth values"


John Stockwell said...

Aristotelian logic, as does propositional
logic (aka lower predicate calculus) depends on the principle of the excluded middle
holding. If the elements of your statements do not have a definite truth value such
that ~A and A is true, then all propositions are simultaneously true and simultaneously false in such a system.

Douglas Groothuis, Ph.D. said...

Theological statements derived from the Bible have nonambiguous truth value if carefully articulated. A statement need not be empirically verifiable to have truth value. Nor does it have to be empirically verifiable to be verifiable in other ways. "Killing the innocent for pleasure" has a truth value: false. It can be known to be false by moral intuition.

Similarly, theological statements can have specifiable meaning. If God is triune (three in one), God is not unitarian. If God is perfectly good, then God is not evil. And so on. Logical consistency is a necessary, but negative test for truth--for theology, philosophy, physics, or anything else. Moreover, one can argue for truth of propositions about God from philosophical, experience, history, and more.

John Stockwell said...

...or perhaps the adoption of an Aristotelian model of logic for interpreting the Bible has created a set of interpretations that force the articulation to be reordered in a particular way, as to
remove contradiction?