3

1

Let's just say we have an implied premise:

2.a Socrates is a philosopher (implied premise), but not explicit

Then is the following a formal fallacy?

- Socrates is a man.
- All men are mortal.
- Socrates is a mortal philosopher.

?

If it is, then you would have to say that the following is a fallacy too because some premises are implied and not express:

- John likes playing football
- John's friends also like playing football
- John plays football with his friends.

Implied premises:

- John plays football because he like to.
- John's friends play football because they like to.
- John and his friends play football together.

Or to make it simpler, the following would also have to be a fallacy:

- My dog is happy when I look after him.
- I always look after my dog.
- Therefore my dog is happy.
2.a My dog is not happy when he injures himself (implied premise).

It seems to me that if implied premises don't count in the construction of a valid conclusion, then nearly every system of arguments is a fallacy because all information and premises are hardly ever given. So what about the Socrates example?

Edit: Sorry for making this long, but if implied premises can count, then there can't be fallacies:

- If P then Q
- Not P, therefore not Q.

Implied premises:

1a. If M, then Q.

1b. M.

Yes: if 2a is not explicitly stated, the argument 1-3 is not formally valid. – Mauro ALLEGRANZA – 2018-04-07T09:35:02.723

@MauroALLEGRANZA So all of my examples are fallacies then? Including the dog one and the football one? – Zebrafish – 2018-04-07T09:40:00.887

@MauroALLEGRANZA Even if the conclusion happens to be true? – Zebrafish – 2018-04-07T09:41:43.037

1

See Valid argument: "In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false. It is not required that a valid argument have premises that are actually true, but to have premises that, if they were true, would guarantee the truth of the argument's conclusion."

– Mauro ALLEGRANZA – 2018-04-07T09:51:22.867Abbout the last example "If M, then Q" and "M", we can use them as premise of a

validargument concluding with "Q". – Mauro ALLEGRANZA – 2018-04-07T10:14:48.493