PHL111: Valid Reasoning
Professor: Craig DeLancey
Office: Campus Center 212A
Office Hours: MWF 1:30 a.m. -- 3:00 p.m. and by appointment
This class is an introduction to formal or symbolic logic. This is
the branch of philosophy that attempts to understand as clearly and
precisely as possible the nature of good reasoning. Becoming skillful
in logic is extremely useful, as good reasoning is essential to every
endeavor you may undertake in life. We will study formal logic
through developing some precise logical languages and then seeing how
these languages can help us reason precisely.
We'll be using the following text, which will be available for free as
an electronic text:
A Concise Introduction to Logic, Craig DeLancey
We will also be using clickers. These are required and are available
in the bookstore. They cost less than a logic textbook would have; I
recommend that you keep them, since you may find you can use them in
Assignments and exams
You will have two exams, two quizzes, and weekly homework
Logic is a discipline that requires practice, which is why we want to
to frequent homeworks. They will be graded strictly, in order to make
clear what you have done correctly and what not; but your overall
homework grade will be curved. Also, note that I will typically give
you questions about material we have not discussed in class yet. This
is a way to get you to think about the material before the lecture, so
that you are better aware of what the lecture is about, what you need
to understand from the lecture, what you may be failing to understand,
and so on.
You can work together, but you must write up your homeworks by
yourself. This means that you will not get credit for identifiably
If you have a disabling condition which may interfere with your
ability to successfully complete this course, please contact the
Disability Services Office.
SUNY mandates attendance for your classes. They also ask me to take
attendance, which I will do by periodically passing around sign-in
sheets or using the clickers to track who is present.
However, I do not grade you for attendance.
Please note the following very important fact: I respect you and
believe you should be allowed to manage your own time. But because I
treat you with respect I demand that you act like you deserve that
respect. That is: do not come to class to talk to the person next to
you, to text message your friends back in the dorm, to surf Youtube,
to read the newspaper. I consider this profoundly disrespectful, it
distracts me a great deal, and it distracts the people around you.
You can do these things somewhere else and I won't penalize you for
doing so; so just stay in your dorm room, or go to the cafeteria, or
anywhere else, if you want to do these things. Class time is for
Of course, I understand that people like to talk to each other during
class about class, asking their neighbor "what did DeLancey just say?"
and so on. That's good -- in the best of all worlds we would all be
doing that often during class. But manners require some taste and I'm
sure you can show good taste in not overdoing that kind of talk to the
point where I can't tell whether you're discussing logic or discussing
Similarly, don't come to class simply to leave after you hand in your
homework, or come twenty minutes late, and so on. That's very
I regret that I delete all the following emails and their equivalents
unanswered: "I missed class today, can you tell me everything you
said?" "I can't find the web site, can you type up the problems and
email them to me?" "I know you don't accept the written homeworks by
email, but can I email my homework just this once?" "I'm emailing my
homework and will come to class sometime and give you the hardcopy
then." "My roommate is in the hospital can you tell me whether I need
to come to class today?" "Will we do anything important in class on
September 29th?" And so on. You get the gist.
If you miss an exam and have an excused absence for the day you miss
the exam, you may make it up, by special appointment with me, when you
are able to come back to class. It is your responsibility to arrange
any make-up exams as soon as you know you are going to miss the
exam. Otherwise you may lose the opportunity to take the test, since I
cannot give make-up exams after the class has gone over the
Here is how you secure an excused absence: Only prior notification
with credibly documented or easily verifiable reasons (e.g., medical
visits to Mary Walker, documented participation in official sporting
events, etc.) will result in excused absences. You must notify in
writing, call, or email me prior to your absence from class. You must
notify the Philosophy Dept. secretary, Pat Meleski, before you are
going to be absent, via email at firstname.lastname@example.org, or by phone at
x2249. However, you must make sure she knows your name, the number of
the course, the date, and your easily verifiable reason, along with a
request to forward the information to me. It is better to give your
information to me, except when you are unable to communicate with my
phone or email for some reason.
The raw grade will be determined in the following way:
Homework assignments: 40%
The quizes will not be announced.
Quizes: 20% (10% each)
Exams: 40% (20% each)
See my grading policy for a brief note
on how I turn the raw grade into a final grade.
Homeworks will typically be returned to you graded, and reviewed, in
the class immediately after you hand it in. We will then review them
together in that class. Homeworks will never be accepted after they
have been reviewed.
You can always drop off a homework early by bringing it to my office.
The secretary can put it in my mailbox; or, if no one is in, you can
slide it under the door if it is clearly marked "FOR DELANCEY."
Please hold onto all of your assignments and exams. Sometime before
the end of the semester I recommend that you ask me to review the
grades that I have recorded to make sure that I have not made any
mistakes. I'm only human and can make typos in recording grades!
Grades will be put up on Angel, so you can and should check these.
Any forms of cheating will earn a zero grade, and will be reported
to the Dean.
College Policy on Intellectual Integrity
Intellectual integrity on the part of all students is basic to
individual growth and development through college course work. When
academic dishonesty occurs, the teaching/learning climate is seriously
undermined and student growth and development are impeded. For these
reasons, any form of intellectual dishonesty is a serious concern and
is therefore prohibited.
The full intellectual integrity policy can be found at
I will frequently update an online schedule of readings and
yassignments. It is your responsibility to check the www pages for
the class at least every other day!
Please leave your phones and pads at home. They are just a
distraction to you and the people around you. I would ask you not
bring a computer either (you can't easily take notes on it, because we
use strange symbols) but some people claim to need them. Since I
don't take attendance, this is not a tough policy: stay in your dorm
room if you want to text message or check your email.
In addition to the listed office hours, I encourage you to make
appointments. I am available quite a bit. Please try to come to
office hours with specific questions in mind. You can of course come
with a general request for help, but it is always helpful if you spend
a little time thinking about how I can best help you out.
In this class, it is your responsibility to learn,
and to be able to describe, explain, and apply:
- what a valid and sound argument are;
- all the elements of our language (terms, connectives,
predicates, quantifiers, and maybe functions), their syntax
(how they combine with other elements to make well formed
formulas), and their semantics (in the case of connectives,
this means their truth tables);
- the inference rules we create to draw inferences from
- how to translate simple English arguments into FOL;
- the four proof methods and how to use them;
- how to complete some original and novel formal proofs;
- how to create your own valid arguments in English for
- Some examples of applications of logic to philosophical problems.