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Introduction to Logic
with David Gordon
Lecture 2
Mises Academy
February 15, 2012
When you heard the terrible news from
Arizona, were you completely surprised? Or
were you, at some level, expecting something
like this atrocity to happen?. . . Last spring
Politico.com reported on a surge in threats
against members of Congress, which were
already up by 300 percent. A number of the
people making those threats had a history of
mental illness  but something about the
current state of America has been causing far
more disturbed people than before to act out
their illness by threatening, or actually
engaging in, political violence.
And theres not much question what has
changed. As Clarence Dupnik, the sheriff
responsible for dealing with the Arizona
shootings, put it, its the vitriolic rhetoric that
we hear day in and day out from people in the
radio business and some people in the TV
business. The vast majority of those who
listen to that toxic rhetoric stop short of actual
violence, but some, inevitably, cross that line.
When you heard the terrible news from Arizona, were you
completely surprised? Or were you, at some level, expecting
something like this atrocity to happen?. . . Last spring Politico.
com reported on a surge in threats against members of
Congress, which were already up by 300 percent. A number of
the people making those threats had a history of mental illness
 but something about the current state of America has been
causing far more disturbed people than before to act out
their illness by threatening, or actually engaging in, political
violence. And theres not much question what has changed.
As Clarence Dupnik, the sheriff responsible for dealing with the
Arizona shootings, put it, its the vitriolic rhetoric that we hear
day in and day out from people in the radio business and some
people in the TV business. The vast majority of those who
listen to that toxic rhetoric stop short of actual violence,
but some, inevitably, cross that line.
 Krugman says that an increase in toxic rhetoric will
inevitably cause some people to cross the line into
violence. But even if an increase in toxic rhetoric
increases the probability that some people will cross
the line, this doesnt show: 1) that the increase in
rhetoric makes it likely that someone will cross the line
or 2) that the increase in rhetoric causes someone to
cross the line.
 Krugman has committed an ignoratio elenchi. He is
trying to show that the increase in toxic rhetoric
causes an increase in violence. He instead shows
something else, i.e., that an increase in rhetoric
increases the chances that someone will be violent.
 Increase the chances does not imply makes
probable
 Makes probable does not imply causes
The first lesson is that property is
originally communal (owned by the
community). Indeed, the very idea of a
purely private property is a contradiction
in terms, since the right to private property
must be recognized by the community to
have any value. For example, the owner
must be able to call upon the police to be
able to exclude others from his property,
or his property cannot be said to be
private at all.
M辿daille, Toward a Truly Free Market
 The first lesson is that property is originally communal
(owned by the community).Indeed, the very idea of a
purely private property is a contradiction in terms, since
the right to private property must be recognized by the
community to have any value. For example, the owner
must be able to call upon the police to be able to
exclude others from his property, or his property cannot
be said to be private at all.
--M辿daille, Toward a Truly Free Market
 The author claims that private property is
originally communal, but he argues instead for
something else---that the community must
recognize private property if it is to have value.
Again, an ignoratio elenchi.
 A Judgment affirms or denies an attribute of
a subject.
 A Proposition is the verbal expression of a
Judgment.
 In Two Name Scholastic Logic, both subject
and predicate name the same thing.
In Socrates is mortal, both Socrates and
mortal are names of the same entity, i.e.,
Socrates. Mortal is a way of referring to
Socrates in this proposition.
If its impossible to combine a predicate with a
subject, the proposition isnt allowed. All dogs
are reptiles is not a legitimate proposition.
 In Two names Logic the verb is always is
or is not.
 This is one of the main areas where
Scholastic Logic differs from mathematical
logic. Frege and Russell thought that
subject-predicate logic cant handle
relations.
We thus have to change, Hitler invades Russia
to Hitler is invading Russia. Otherwise, the
proposition cant be analyzed properly in this kind
of Logic.
The copula is indicates the existence or being,
of the subject, but this doesnt have to be
existence in reality. It can be existence in the
mind. e.g., Hamlet was indecisive.
 Quantity of propositions:
 A Universal affirmative
 I Particular affirmative
 E Universal negative
 O Particular negative
 Its very important to learn this table,
because the Scholastic analysis of the
syllogism depends on this classification.
 Some propositions are hard, but not
impossible to classify, e.g., Singular
Propositions, Complex Propositions,
and Compound propositions.
 Joyce says that in an analytic proposition,
either: the predicate is contained in the
intension of the subject, or the subject in the
intension of the predicate.
 A simpler way to understand this is that in an
analytic proposition, the predicate is part of the
concept of the subject or follows from the
concept of the subject.
 Different from the logical positivist view that
analytic propositions are conventional.
 A synthetic proposition is one in which there isn
t a conceptual connection between the subject
and predicate.
 Two meanings of possible
 Hypothetical propositions
 Disjunctive propositions
"If there is a dominant theme that runs
through our discussion, it is this: Private
property is a legal convention, defined in
part by the tax system; therefore, the tax
system cannot be evaluated by looking at its
impact on private property, conceived as
something that has independent existence
and validity. Taxes must be evaluated as
part of the overall system of property rights
that they help to create. . . The conventional
nature of property rights is both perfectly
obvious and remarkably easy to forget . . .
We cannot start by taking as given . . . some
initial allocation of possessions what
people own, what is theirs, prior to
government interference"
Liam Murphy and Thomas Nagel, The Myth
of Ownership (Oxford, 2002), p.8
"If there is a dominant theme that runs through our
discussion, it is this: Private property is a legal
convention, defined in part by the tax system; therefore,
the tax system cannot be evaluated by looking at its
impact on private property, conceived as something that
has independent existence and validity. Taxes must be
evaluated as part of the overall system of property rights
that they help to create. . . . The conventional nature of
property rights is both perfectly obvious and remarkably
easy to forget . . . We cannot start by taking as given . . .
some initial allocation of possessions what people
own, what is theirs, prior to government interference"
 Murphy and Murphy are begging the
question: they are claiming that property
rights are conventional because property
rights are conventional.
 Note: Beg the question does not mean
raise the question.
Because in fact these high tax
economies actually do well, it follows
that what happens in the real world is
that much of that tax money is spent
constructively, on programs that
inspire a sense of confidence,
improve productivity, and promote
good health and education.
--Jeff Madrick, The Case for Big Government,
Princeton, 2009, p.17
This is the famous post hoc, ergo propter
hoc fallacy. If the government imposes high
taxes and the economy then did well, it
doesnt follow that the high taxes contributed
to the prosperity
Suppose there were a 100-percent probability
that unless prevented, a terrorist known to be
loose in Manhattan would explode a nuclear
bomb. No sane person would balk at
abandonment of the conventional limitations on
the power to search and seize and the power to
extract information from suspects and even
bystanders. Would he refuse to countenance
an exception for a lesser threat to public
safety? If the probability were 99 percent rather
than 100 percent, could he sanely adhere to
that position? Eventually, a rule and exception
approach would dissolve into balancing, and
disagreement would shrink to differing
assessments of the risks and harms
--Richard Posner, Law, Pragmatism, and
Democracy, (Harvard University Press, 2003),
pp. 315-16.
"Suppose there were a 100-percent probability that
unless prevented, a terrorist known to be loose in
Manhattan would explode a nuclear bomb. No sane
person would balk at abandonment of the conventional
limitations on the power to search and seize and the
power to extract information from suspects and even
bystanders. Would he refuse to countenance an
exception for a lesser threat to public safety? If the
probability were 99 percent rather than 100 percent,
could he sanely adhere to that position? Eventually, a
rule and exception approach would dissolve into
balancing, and disagreement would shrink to differing
assessments of the risks and harms"
 This is an example of the misuse of the
sorites paradox.
 If you start with a completely bald man
and then add one hair, isnt the person
still bald? But adding one hair cant
change whether someone is bald.
Therefore, someone with a full head of
hair is bald.
Richard Posner responds the objection to judicial
review that it permits elitist judges to impose their
values on the rest of us in this way:
"Liberalism is in tension with democracy.
Democracy is a means not only of dispersing
political power and thus of protecting the private
sphere against invasion by the public sphere, but
also of enabling people to enforce their dislike of
other people's self-regarding behavior
--Richard Posner, Overcoming Law, (Harvard, 1995), p.25.
This is an ignoratio elenchi. Posner says
there are problems with democracy. But even
if he is right, this doesnt respond to the point
about elitist judges.

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How to Think: Introduction to Logic, Lecture 2 with David Gordon - Mises Academy

  • 1. Introduction to Logic with David Gordon Lecture 2 Mises Academy February 15, 2012
  • 2. When you heard the terrible news from Arizona, were you completely surprised? Or were you, at some level, expecting something like this atrocity to happen?. . . Last spring Politico.com reported on a surge in threats against members of Congress, which were already up by 300 percent. A number of the people making those threats had a history of mental illness but something about the current state of America has been causing far more disturbed people than before to act out their illness by threatening, or actually engaging in, political violence. And theres not much question what has changed. As Clarence Dupnik, the sheriff responsible for dealing with the Arizona shootings, put it, its the vitriolic rhetoric that we hear day in and day out from people in the radio business and some people in the TV business. The vast majority of those who listen to that toxic rhetoric stop short of actual violence, but some, inevitably, cross that line.
  • 3. When you heard the terrible news from Arizona, were you completely surprised? Or were you, at some level, expecting something like this atrocity to happen?. . . Last spring Politico. com reported on a surge in threats against members of Congress, which were already up by 300 percent. A number of the people making those threats had a history of mental illness but something about the current state of America has been causing far more disturbed people than before to act out their illness by threatening, or actually engaging in, political violence. And theres not much question what has changed. As Clarence Dupnik, the sheriff responsible for dealing with the Arizona shootings, put it, its the vitriolic rhetoric that we hear day in and day out from people in the radio business and some people in the TV business. The vast majority of those who listen to that toxic rhetoric stop short of actual violence, but some, inevitably, cross that line. Krugman says that an increase in toxic rhetoric will inevitably cause some people to cross the line into violence. But even if an increase in toxic rhetoric increases the probability that some people will cross the line, this doesnt show: 1) that the increase in rhetoric makes it likely that someone will cross the line or 2) that the increase in rhetoric causes someone to cross the line.
  • 4. Krugman has committed an ignoratio elenchi. He is trying to show that the increase in toxic rhetoric causes an increase in violence. He instead shows something else, i.e., that an increase in rhetoric increases the chances that someone will be violent. Increase the chances does not imply makes probable Makes probable does not imply causes
  • 5. The first lesson is that property is originally communal (owned by the community). Indeed, the very idea of a purely private property is a contradiction in terms, since the right to private property must be recognized by the community to have any value. For example, the owner must be able to call upon the police to be able to exclude others from his property, or his property cannot be said to be private at all. M辿daille, Toward a Truly Free Market
  • 6. The first lesson is that property is originally communal (owned by the community).Indeed, the very idea of a purely private property is a contradiction in terms, since the right to private property must be recognized by the community to have any value. For example, the owner must be able to call upon the police to be able to exclude others from his property, or his property cannot be said to be private at all. --M辿daille, Toward a Truly Free Market The author claims that private property is originally communal, but he argues instead for something else---that the community must recognize private property if it is to have value. Again, an ignoratio elenchi.
  • 7. A Judgment affirms or denies an attribute of a subject. A Proposition is the verbal expression of a Judgment. In Two Name Scholastic Logic, both subject and predicate name the same thing. In Socrates is mortal, both Socrates and mortal are names of the same entity, i.e., Socrates. Mortal is a way of referring to Socrates in this proposition. If its impossible to combine a predicate with a subject, the proposition isnt allowed. All dogs are reptiles is not a legitimate proposition.
  • 8. In Two names Logic the verb is always is or is not. This is one of the main areas where Scholastic Logic differs from mathematical logic. Frege and Russell thought that subject-predicate logic cant handle relations. We thus have to change, Hitler invades Russia to Hitler is invading Russia. Otherwise, the proposition cant be analyzed properly in this kind of Logic. The copula is indicates the existence or being, of the subject, but this doesnt have to be existence in reality. It can be existence in the mind. e.g., Hamlet was indecisive.
  • 9. Quantity of propositions: A Universal affirmative I Particular affirmative E Universal negative O Particular negative Its very important to learn this table, because the Scholastic analysis of the syllogism depends on this classification. Some propositions are hard, but not impossible to classify, e.g., Singular Propositions, Complex Propositions, and Compound propositions.
  • 10. Joyce says that in an analytic proposition, either: the predicate is contained in the intension of the subject, or the subject in the intension of the predicate. A simpler way to understand this is that in an analytic proposition, the predicate is part of the concept of the subject or follows from the concept of the subject. Different from the logical positivist view that analytic propositions are conventional. A synthetic proposition is one in which there isn t a conceptual connection between the subject and predicate.
  • 11. Two meanings of possible Hypothetical propositions Disjunctive propositions
  • 12. "If there is a dominant theme that runs through our discussion, it is this: Private property is a legal convention, defined in part by the tax system; therefore, the tax system cannot be evaluated by looking at its impact on private property, conceived as something that has independent existence and validity. Taxes must be evaluated as part of the overall system of property rights that they help to create. . . The conventional nature of property rights is both perfectly obvious and remarkably easy to forget . . . We cannot start by taking as given . . . some initial allocation of possessions what people own, what is theirs, prior to government interference" Liam Murphy and Thomas Nagel, The Myth of Ownership (Oxford, 2002), p.8
  • 13. "If there is a dominant theme that runs through our discussion, it is this: Private property is a legal convention, defined in part by the tax system; therefore, the tax system cannot be evaluated by looking at its impact on private property, conceived as something that has independent existence and validity. Taxes must be evaluated as part of the overall system of property rights that they help to create. . . . The conventional nature of property rights is both perfectly obvious and remarkably easy to forget . . . We cannot start by taking as given . . . some initial allocation of possessions what people own, what is theirs, prior to government interference" Murphy and Murphy are begging the question: they are claiming that property rights are conventional because property rights are conventional. Note: Beg the question does not mean raise the question.
  • 14. Because in fact these high tax economies actually do well, it follows that what happens in the real world is that much of that tax money is spent constructively, on programs that inspire a sense of confidence, improve productivity, and promote good health and education. --Jeff Madrick, The Case for Big Government, Princeton, 2009, p.17 This is the famous post hoc, ergo propter hoc fallacy. If the government imposes high taxes and the economy then did well, it doesnt follow that the high taxes contributed to the prosperity
  • 15. Suppose there were a 100-percent probability that unless prevented, a terrorist known to be loose in Manhattan would explode a nuclear bomb. No sane person would balk at abandonment of the conventional limitations on the power to search and seize and the power to extract information from suspects and even bystanders. Would he refuse to countenance an exception for a lesser threat to public safety? If the probability were 99 percent rather than 100 percent, could he sanely adhere to that position? Eventually, a rule and exception approach would dissolve into balancing, and disagreement would shrink to differing assessments of the risks and harms --Richard Posner, Law, Pragmatism, and Democracy, (Harvard University Press, 2003), pp. 315-16.
  • 16. "Suppose there were a 100-percent probability that unless prevented, a terrorist known to be loose in Manhattan would explode a nuclear bomb. No sane person would balk at abandonment of the conventional limitations on the power to search and seize and the power to extract information from suspects and even bystanders. Would he refuse to countenance an exception for a lesser threat to public safety? If the probability were 99 percent rather than 100 percent, could he sanely adhere to that position? Eventually, a rule and exception approach would dissolve into balancing, and disagreement would shrink to differing assessments of the risks and harms" This is an example of the misuse of the sorites paradox. If you start with a completely bald man and then add one hair, isnt the person still bald? But adding one hair cant change whether someone is bald. Therefore, someone with a full head of hair is bald.
  • 17. Richard Posner responds the objection to judicial review that it permits elitist judges to impose their values on the rest of us in this way: "Liberalism is in tension with democracy. Democracy is a means not only of dispersing political power and thus of protecting the private sphere against invasion by the public sphere, but also of enabling people to enforce their dislike of other people's self-regarding behavior --Richard Posner, Overcoming Law, (Harvard, 1995), p.25. This is an ignoratio elenchi. Posner says there are problems with democracy. But even if he is right, this doesnt respond to the point about elitist judges.