Contradictory premises/Pulling the carpet II
Part II of a posting from 2016.
Thursday, August 04, 2016: Contradictory premises: Pull the carpet...
Contradictory premises
From
PIRIE, MADSEN (2006)(2015) How To Win Every Argument, Bloomsbury, London.
'The problem with contradictory premises is that they cannot both be true. If one is true, the other must be false, and vice versa. In other words, we can be certain that at least one of them must be false, and cannot generate a sound argument.' (69). We do not need to see the conclusion here, we already reasonably know, that at least the premises are contradictory. One premise might be true, but not both. A valid argument can have a false premise. (69). As long as the premise (s) are not true and the conclusion false, it is logically possible to have a valid argument.
Premise-Conclusion
TT, FF, FT, TF
A true premise (s) and false conclusion (TF) from these combinations, cannot possibly be logically valid.
However, as Pire recognizes, a sound (true) argument has all true premises. (69). It has a true conclusion.
The classic 'the moon is made of green cheese' (69), is documented as a valid premise, but not a premise in a sound (true) argument. It is not reasonable from empirical, scientific evidence that the moon is made of green cheese, but it is not an illogical premise as such.
I have suggested to my friends that in arguments, when one disagrees with the conclusion, deny a premise first, if that can be reasonably, truthfully done. This pulls the carpet. It prohibits one from being dragged into accepting a questionable conclusion after hastily accepting premises and then having to philosophically backtrack...
Here is a common, paraphrased, psychological, motivational, premise and conclusion.
Premise
You are the main creator of your life.
Conclusion
Therefore, if it is going to be, it is up to you.
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I deny the premise and pull the carpet, by stating:
God is infinite.
God is necessary.
God is the primary cause of all things.
A human being is finite.
A human being is contingent (dependent on what is necessary as the sufficient cause).
A human being is a secondary cause (of some things).
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I also deny the conclusion, simultaneously. If it is going to be, it is secondarily up to you.
Cited
Confusion of Necessary with a Sufficient Condition
A causal fallacy you commit this fallacy when you assume that a necessary condition of an event is sufficient for the event to occur. A necessary condition is a condition that must be present for an event to occur. A sufficient condition is a condition or set of conditions that will produce the event. A necessary condition must be there, but it alone does not provide sufficient cause for the occurrence of the event. Only the sufficient grounds can do this. In other words, all of the necessary elements must be there.
Cited
I don't know why the car won't run; I just filled the gas tank.
A sufficient condition is a condition or set of conditions that will produce the event.
The vehicle needs to be started too. A missing premise.
I reason that as God is the necessary cause of all things, directly or indirectly, God is also the sufficient cause of all things. As a theistic philosopher of religion and theologian within the Reformed tradition, everything that occurs is caused by God, either directly willed, or indirectly willed, which could also be called, allowed.
Necessary versus Sufficient conditions
Philosopher Blackburn explains...
'If p is a necessary condition of q, then q cannot be true unless p is true. If p is a sufficient condition of q, then given that p is true, q is so as well.' (73). Blackburn provides the example: Steering well is a necessary condition of driving well... (73). But it is not sufficient, as one can steer well, but be an overall bad driver. (73). Perhaps, one steers very well, but is overly occupied by texting while driving. (My add, and not my practice)
This concept from Blackburn with the use of symbolic logic, provides a level of complexity, yet consistent and logical at the same time. But providing a true example provides another level of difficulty.
A solid/true example
Infinite attributes (a) are a necessary condition of infinite nature (b).
Infinite attributes (a) are a necessary condition of infinite nature (b), then infinite nature (b) cannot be true unless infinite attributes (a) are true. If infinite attributes (a) are a sufficient condition of infinite nature (b), then given that infinite attributes (a) are true, then infinite nature (b) is so as well.
BLACKBURN, SIMON (1996) Oxford Dictionary of Philosophy, Oxford, Oxford University Press.
CONWAY DAVID A. AND RONALD MUNSON (1997) The Elements of Reasoning, Wadsworth Publishing Company, New York.
LANGER, SUSANNE K (1953)(1967) An Introduction to Symbolic Logic, Dover Publications, New York.
PIRIE, MADSEN (2006)(2015) How To Win Every Argument, Bloomsbury, London.
Edited for an entry on academia.edu, April 22, 2022
Excellent
ReplyDeleteDavid, thanks as always.
ReplyDelete