Is logic the most powerful debating device?

All premises can be reasonably denied except self-existence, so all debates ultimately start with some form of “I believe X”, irrespective of how absurd it would seem to hypothetically deny X. (e.g. one such denial could be ‘Sun and Moon are the same celestial object’). In this respect, regular debates are no different than ontological debates.

What is true is that ethical and religious beliefs are mostly held with deep conviction. This is because they are engraved and solidified by years of sense experiences. Which means that you can’t logically reason them out in a 2 hour debate but that doesn’t mean they are not logically derived from source observations. Using logic, you could show a alternate but consistent way to interpret those same observations, thus influencing/changing those deeply-held beliefs.

Realistically, only for the first few months after freshman Philosophy 101, after which the effect wears off.

In through one ear, out through the other.

I would say further that regardless of soundness-of-logic, no conclusion of a dialectical process can attain a more valid status than thesis if the conclusion cannot be demonstrated empirically.

… I think quite a bit of people would disagree that 1) all can be denied and quite a few others would suggest that 2) self-existence is easily denied, depending on how you define the term.

1)“it only appears that way” :slight_smile:

2)I don’t mean the self-as-identity, rather the self-as-perceiver.

When I was studying rhetoric in college, we were taught that the Ancient Greeks had greater respect for emotional arguments than strictly logical ones. And I think that in many cases, emotional appeals work better than logic. Of course, a good emotional appeal won’t be completely devoid of logic, but if your purpose is to persuade someone of something then it’s important to make them care about it.

As erislover has already described, a perfectly valid logical argument may fail to be convincing. Perhaps one of the most difficult to overcome is when your audience just doesn’t buy your logic. There’s a reason why people have to study formal logic, and a reason why there are so many known and named logical fallacies. Just because something is logical doesn’t mean it’s easy to understand.

A very common fallacy I’ve seen come up even on these hallowed boards is Denying the Antecedent. “If A, then B. A is not true. Therefore, B is not true either.” This is an invalid argument because our premises don’t show that A is strictly necessary for B to be true. It may be true that whenever A is true then B is true too, but there could be other factors that would make B true even in A’s absence. A might not even have anything to do with B in the first place. But this kind of argument, although it’s invalid, can often be made to sound convincing.

If there is a single most powerful debating device, that’s probably it: sounding convincing.

And how do we appeal to the “emotional” aspect of our argument, Lamia? Could you propose any examples, as I find the idea a little difficult to grasp? Do you mean the more obvious psychological tactics e.g. shouting; rhetoric; looking good etc. ? Or something similiar?

2 + 2 = 4, - Logic

.9999 = 1, - Argument

You find the idea of an emotional appeal difficult to grasp? I must say, I find that a bit difficult to grasp. Perhaps I am misunderstanding you. People make emotional appeals in debates all the time. Indeed, it would be a pretty dry debate if no one had any emotional investment in the issue. As for an example, here’s the first one that springs to mind: “Would you still be against the death penalty if it were your daughter who’d been brutally raped and murdered?”

Well, those too, but I wasn’t thinking of any of that except perhaps rhetoric. (“Rhetoric” seems a bit out of place in your list to me, so I’m not sure you mean the same thing I do with the term.) Any time a debate participant asks people to image how they’d feel in a particular situation, they’re making an emotional appeal. Same for evoking sympathy, concern, shame, or fear. Heck, make people laugh and you may get them on your side.

You don’t have to be right to win a debate. If there were an obvious “right” position, there wouldn’t need to be a debate in the first place. It certainly helps to have the stronger logical argument on your side, but you don’t win if you present a perfectly valid argument that no one cares about or understands. It’s the person who’s more persuasive who wins.

Logic is an important tool in debating, but it is very far from the whole story. There are other elements that are not logical but may carry the day, such as appeal to emotion, appeals to authority, precedent or tradition, empiricism, appeals to utilitarianism or aesthetics, personal attacks, aphorisms and violence. I believe they all have a place, except for aphorisms.

A couple of example “debates” to illustrate:

An engineer is proudly observing the bridge he has just completed. A second engineer talks to him:

2ND ENGINEER: How do you know your bridge is safe?

1ST ENGINEER: We calculated the maximum stresses and designed it based on the strength of the steel, with a safety factor of five. (Logical argument.)

2ND ENGINEER: How do you know a safety factor of five is enough?

1ST ENGINEER: It’s what the code stipulates. (Appeal to authority, which itself is based on empiricism and precedent.)

2ND ENGINEER: How did you calculate the maximum stresses?

1ST ENGINEER: We assumed nose-to-tail trucks carrying maximum permitted loads on both lanes.

2ND ENGINEER: What about nose-to-tail trucks on just one lane? Won’t that unbalance the bridge? (Proposing an addittional premise, implies current premises are insufficient.)

1ST ENGINEER: We took that into account.

2ND ENGINEER: What about force amplification by resonance?

1ST ENGINEER: We thought of that, the natural frequency is too high for it to happen.

2ND ENGINEER: What about a spill of burning gasoline?

1ST ENGINEER: It’ll take it.

2ND ENGINEER: A liquid oxygen spill that ignites the tarmac and steel itself?

1ST ENGINEER: (Becoming annoyed.) You’re not allowed to transport liquid oxygen by road.

2ND ENGINEER: Fuming nitric acid spill? Earthquake? Terrorist bomb? Plane crash? Meteorite impact?

1ST ENGINEER: Drops 2ND ENGINEER with one punch.
The second engineer has a valid point in that you can’t design for every contingency. The first engineer could have pointed out that a degree of pragmatism is required and you have to let some contingencies ride, but this is just as open to logical attack. Recognising that the 2nd engineer could continue forever and was deliberately being a pain, he opted for a succinct and practical communication of his feelings. Who won is itself a matter of debate; being a fan of utilitarianism myself, I’d give it to the first engineer.
My second example debate is between the 1st engineer and a philosopher:

PHILOSOPHER: How do you know your bridge is safe?

ENGINEER: We calculated the maximum stresses and designed it based on the strength of the steel, with a safety factor of five. (Logical argument again.)

PHILOSOPHER: How do you know that the strength of the steel won’t change suddenly? (Attacking a premise.)

ENGINEER: It has never been observed to change suddenly. Also, if materials changed strength suddenly and arbitrarily, it would have affected the development of the planets and the universe. There would be geological and astronomical evidence for it. (Appeal to precedent.)

PHILOSOPHER: That doesn’t prove that it couldn’t happen. Your assumption that the steel will maintain its properties over time is a matter of faith.

ENGINEER: True. I can’t prove that the universe will remain usefully consistent and predictable in the future, although it has done so up till now. On the other hand you seem to hold the same beliefs as me - I don’t see you clinging to the ground in case gravity suddenly reverses itself. (Personal attack, essentially accusing the philosopher of hypocrisy.)

PHILOSOPHER: Consistency is the hobgoblin of small minds! (Aphorism - an irritating and essentially invalid debating tactic, IMO, and probably worthy of another punch.)

ENGINEER: Whatever. Cross the river however you like. I’m going to use the bridge and take my chances with the universe. (Appeal to utilitarianism. What’s the quote about philosophers and toothache?)
Again, the philosopher is logically completely correct - the engineer’s belief in his calculations, the strengths of materials, the forces of gravity etc. are based on precedent, which doesn’t PROVE anything. His rebuttal is a pragmatic one rather than a logical one.
That’s enough rambling from me. I was going to start on about how Spock’s sacrifice at the end of Wrath of Khan wasn’t purely logical - his “the needs of the many outway the need of the few” has an implicit value premise based upon emotion, but I’ll leave it.

That’s pretty interesting matt.

BTW, anyone who has information concerning books on the OP topic, or on what erislover, Lamia or II Gyan II has mentioned, please feel free to… well… er… mention them.
Lamia writes:

I probably should have mentioned I’m stupid. But thanks, you did clear it up for me (my quibble not the stupidity).

Here are two free resources:

1)Causal and Statistical Reasoning


I’d recommend Thomas Gilovich’s How We Know What Isn’t So, which examines the common but faulty kind of reasoning that leads people to firmly believe in things that aren’t true…such as basketball “hot streaks”, or the full moon causing weird goings-on.

If Logic was the best argument, Spock would have been captain, and not Kirk