Wednesday, August 24, 2005

"No Jesus, no peace"

I drove by a church the other day. On the sign out front was this bit of cleverness:

No Jesus, no peace
Know Jesus, know peace

Very nice. But, of course, if "no Jesus, no peace" were true, wouldn't it follow that "no peace, no Jesus" would be true? And, since the world has never been at peace during the entire history of humankind, this seems to indicate that, in fact, there is no Jesus.

I'm just sayin'.


At 6:15 AM, Blogger R. Paul Wiegand said...

In all fairness, logical implication is different than logical equivalence. So it is perfectly reasonable to assert "no Jesus -> no Peace" while not meaning "no Peace -> no Jesus". Still, the two propositions taken together do mean what you suggest, I think, or else they mean something very unintended.

First, consider that they probably do not mean "not Jesus", they really mean "knowledge of" in all cases. I also assume that there is a logical "and" connecting the two statements. That is, these two propositions should, more formally, be written together as:

~knowledgeOf(Jesus) --> ~knowledgeOf(Peace)
knowledgeOf(Jesus) --> knowledgeOf(Peace)

Which we will abbreviate as follows:
(~J->~P) * (J->P)

The truth tables for the two propositions are:

J | P | ~J -> ~P | J -> P
t | t | t | t
t | f | t | f
f | t | f | t
f | f | t | t

The only times these two propositions are true is when both facts are true or both are false ... which is the definition of equivalence. So, in fact, you are right: they mean to suggest that knowledge of peace and knowledge of Jesus are the same thing. Which, in turn, implies that there is no knowledge of Jesus in the world, since there is no Peace in the world.

If they really do mean "not Jesus" then I am certainly confused. By this, I assume, they would mean to suppose the literal lack of existence of Jesus and the literal lack of existence of Peace? If this is true, the two propositions deal with separate facts altogether, and I don't think the implication can be read as an equivalence (necessarily).

Of course that gets them into actual trouble. Since a false premise can imply a true consequent, and since a "false premise" in this first statement is the actual existence of Jesus, it is fair (according to their own premise) to assert that given the fact that Jesus can exist and the fact the there is no peace, the implication still holds. That is, the facts "Jesus exists", "there is no peace" are equally valid as the facts "Jesus exists", "there is peace" ... since, under a false premise, we know nothing about the consequent. This is why I assumed they meant "knowledge of" in all cases. I don't believe they mean to suggest that the only valid factual information that can be induced can come under the case when Jesus does not exist. That is, the first premise would be equivalent to writing, "Hey, if jesus doesn't exist then I know for sure Peace can't exist ... but if he does exist, there's no relationship between Peace and Jesus."

But logic and religion are not really well-suited for each other, in spite of George Santayana's claim that "religion, in its intent, is a more conscious and direct pursuit of the Life of Reason than is society, science, or art."

Of course, he also writes:

"Religion pursues rationality through the imagination. When it explains events or assigns causes, it is an imaginative substitute for science. When it gives precepts, insinuates ideals, or remoulds aspiration, it is an imaginative substitute for wisdom ... the conditions and aims of life are both represented in religion poetically, but this poetry tends to arrogate itself to literal truth and moral authority, neither of which it possesses."

Just a fun quote for the day ...

At 8:01 AM, Blogger mooglar said...

I thought about going into the equivalence (or lack thereof) issue with reversing "no Jesus, no peace," and why, in the end, "no Jesus, no peace" must be logically equivalent to "no peace, no Jesus" if meant in the way I believe it is. But I was wise not to do so, for you have done a much better job, with truth tables and everything. Bravo, sir! :^)


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