P1. All dogs are mammals.This specific form of representing an argument is called a syllogism. In Phil 001, one typically deals with syllogisms. Looking at syllogisms is the best way to grasp the concept of an argument and to get into the habit of thinking in terms of an argument. In today’s lectures, we shall focus exclusively on syllogisms.
P2. All mammals are warm-blooded.
C. Therefore, all dogs are warm-blooded.
This basic idea is very simple. However, learning to think in terms of premises and conclusions is something that takes a great deal of effort and practice for a great many people. For some, it comes quite naturally. But for many people, this is utterly foreign to how one normally thinks, especially about ethics. Many people think of ethics either as simply a matter of following an authority – the state, one’s pastor, common opinion – or as something more like poetry, something that one simply feels. This is not to say that philosophers are emotionless, or that feeling has no role in moral inquiry. But the key to moral discourse, for the philosopher, is reasoned argument.
Before we end today, I want to look at a couple examples of arguments.
I then have a homework assignment for you to complete for Thursday’s lecture.
P1. There are no bears around.Is this a good argument? In assessing whether an argument is good or bad, we look at two things: (1) Are the premises reasonable? (2) Do the premises provide sufficiently compelling grounds for accepting the conclusion? If you happen to have seen this episode of The Simpsons, you will know that the premise is indeed true. But it does not provide good grounds for accepting the conclusion. Lisa demonstrates this by way of counter-example.
C. Therefore, the Bear Patrol is working.
P1. There are no tigers around.In Lisa’s argument, the premise is true, yet the conclusion absurd. Thus, it is a clearly a fallacious argument. Yet it has the very same structure as Homer’s argument. Thus, there must be something wrong with Homer’s argument.
C. Therefore, this rock must be an effective tiger-deterrent.
Be careful. For an argument to be cogent, it is not sufficient
that the conclusion be true. The argument must be such that the premises
provide sufficient reasons or grounds for accepting the conclusion.
Consider the following argument:
P1. Almost all mammals are warm-blooded.
P2. Warm-blooded animals tend birth their young life (as opposed to laying eggs).
C. Therefore, almost all mammals have fur or hair.
Even though the premises and conclusion are all true, the argument
is not cogent, as the premises do not provide good grounds for accepting
the conclusion. Rather, we all accept the conclusion because that
is what we learned in biology class (and we believed our teachers).
Now the above example is rather silly, and one not likely to be confused
with a good argument. But it is important to keep this in mind when
analyzing moral arguments, as we are likely to accept an argument simply
because we agree with the conclusion (and so are typically willing to accept
the premises as well). Consider the following:
P1. We cannot be soft on violent criminal behaviour.This is not a good argument, because there is nothing that connects the premises to the conclusion. One who already accepts the conclusion will be tempted to view this as a good argument. And it may even psychologically resonate with how one thinks about the issue. But, based on the objective logical structure, the argument is not cogent. In contrast the following is much better:
P2. We must do all we can to protect society from violent criminals.
C. Therefore, we must institute minimum sentences for certain violent crimes.
P1. Instituting minimum sentences for violent crimes will have a deterrent effect on future commissions of those crimes.This is at least a prima facie cogent argument. While there may be good grounds for rejecting it, it at least connects the premises to the conclusion in a plausible manner.
P2. We must do what we can to deter potential criminals from committing violent crimes.
C. Therefore, we must institute minimum sentences for certain violent crimes.
Conditions (ii) and (iii) are important here. The strength of the counter-example depends on how widely it would be accepted that the premises are warranted and the conclusion unwarranted. Lisa’s counter-example, for instance, is very strong, as everyone (except Homer) would accept the premise but reject the conclusion. But when we get into moral debates, one must be more careful. For example, consider the following counter-example to the above argument about minimum sentences:
P1’. Suspending students from university for cheating will have a deterrent effect on future instances of cheating.While many would accept the premises, many would also accept the conclusion. So this is probably not the strongest counter-example that could be made to the above argument.
P2’. We must try to reduce the occurrence of cheating in university.
C’. Therefore, we should suspend students from university for cheating.
P1’’. Instituting the death penalty for excessive speeding will have a deterrent effect on future instances of excessive speeding.Most people would probably accept P1’’. If one is not inclined to accept this premise, then one is probably also not inclined to accept the first premise of the original argument. Remember this is supposed to be a counter-argument to the original argument about minimum sentences. So the intended target here is someone who already accepts that argument. It is likely that anyone who accepts P1 would also accept P1’’. It is also likely that most would reject the conclusion as absurd. What this means is that the proponent of the original argument must revise one of the premises so as to block the counter-argument. And the cycle continues.
P2’’. We must do what we can to protect society from dangerous drivers such as those who drive at excessive speeds.
C’’. Therefore, we should institute the death penalty for excessive speeding.
But the last important point to note about this is the importance of
common ground. In a philosophic argument, progress is best made if
one looks for common ground (e.g. shared beliefs or values) and follows
out the logical implications of those common presuppositions.