Why do we concern ourselves with false
premises? Why we just confine ourselves with
Case 1: In science, we verify theories by deducing
testable consequences from uncertain
theoretical premises, we cannot know
beforehand which theories are
1. A deductive argument is intended to
provide conclusive support for its conclusion.
2. A deductive argument that succeeds in
providing conclusive support for its premise is
said to be valid. A valid argument is such that if
Judging Argumentstelling (1) whether an
argument is deductive or inductive and (2)
whether it gives good reasons for accepting the
Find the arguments conclusion and then its
Ask: Is it the case that if
The relation between the premises and the conclusion
of a deductive argument is: given the premises are
true, the conclusion has to be true.
The characteristic of deductive arguments is truthpreserving.
Expressions such as must, it must be the case that,
necessarily, inevitably, certainly, and it can be deduced
that are frequently used to indicate that an argument is
deductive. The terms entail and imply also signify a
Terms such as m
Most corporation lawyers are conservative.
Mary is a corporation lawyer.
Mary is probably a conservative.
Most dogs have fleas.
Bowser is a dog.
Bower, my dog, probably has fleas.
(1) There is no question in my mind. (2) I therefore
maintain that Colonel Mustard is the murderer. (3)
Because if he did it, he would probably have blood
stains on the sleeve of his shirt. (4) The blood stains
are tiny, but they are there. (5) Any observ
Canada is an extremely spread-out country that depends on road and
air transport to a far greater extent than do European countries. In
European countries rail service can be more efficiently and
economically run than it can in Canada. Without an effectiv
The dominant characteristic of sprawl is that
each component of a community housing,
shopping centers, office parks, and civic
institutionsis segregated, physically separated
from the others, causing the residents of
suburbia to spend an inord
1. An inductive argument is intended to
provide probable support for its conclusion.
2. An inductive argument that succeeds in
providing probable support for its conclusion is
said to be strong. A strong argument is such
that if its pr
I. All men are mortal.
Socrates is a man.
Socrates is mortal
II. Either Jeb is not graduating, or he has paid his tuition bill.
But he is graduating.
He has paid his tuition bill.
III. All deliberate killing of a helpless person is wrong.
Argument in standard form:
1. Write each premise on a line by itself.
2. Underneath the last premise, draw a line.
3. Write the conclusion beneath the line.
The earth is spherical in shape. For the night sky looks different in the
northern and so
A test case of writing an argument in standard form.
In the past there has been much argument whether, in the
strategy of inflation control, one should seek to come to grips
with the level of demand or whether one should seek to deal
with the wage-price s
Inflation could be controlled by a sufficiently heavy reduction
in the level of demand.
It could also be controlled with a less drastic reduction if
something could be done to arrest the inter-reactions of wages
and prices, or, to speak more precisely, of
Is the following passage an argument? What is the conclusion?
What are the premises?
A judgment of acquittal by reason of insanity is appropriate
only when a jury verdict of guilty would violate the law or the
facts. We cannot say that this was the situat
Premise 1: A judgment of acquittal by reason of insanity is
appropriate only when a jury verdict of guilty would violate the
law or the facts.
Premise 2: We cannot say that this was the situation in
Conclusion: The district court did n
When we study arguments, two questions arise:
1. Are the premises true?
2. Would the premises, if true, provide strong
support for the conclusion?
Ideally, we are looking for the situation where all
premises are true, and the conclusion follows
from the p
Now, in the first place, this is evident to those who define
what truth and falsehood are. For indeed, the asserton that
entty does not exist, and that nonentty does, is a falsehood,
but that entty exists, and that nonentty does not exist, is
Diagram the following argument:
There is no question in my mind. I therefore
maintain that Colonel Mustard is the murderer.
Because if he did it, he would probably have
blood stains on the sleeve of his shirt. The blood
stains are tiny, but they are there
Diagramming Arguments: Step by Step
1.Underline all premise or conclusion indicator words
such as since, therefore, and because. Then
number the statements.
2.Find the conclusion and draw a wavy line under it.
3.Locate the premises and underline them.
Contrary to what many people think, (1) a
positive test for HIV is not necessarily a death
sentence. For one thing, (2) the time from the
development of antibodies to clinical symptoms
averages nearly ten years. For another, (3) many
reports are now sugg