Thomas on Fallacies (2)


Chapter 13

The Fallacy of Secundum Quid and Simpliciter

Secundum quid and simplicter. “Simpliciter” here means what is said in no way with an addition, as when it is said Socrates is white and Socrates runs. Secundum quid is said with some addition like “he runs well” or “Socrates is white with respect to his teeth.” What is added stands to what it is added in two ways: (1) Sometimes it does not do away with the ratio of the thing to which it is added and in these cases one can proceed from the secundum quid to the simpliciter, as “he runs quickly, therefore he runs” for speed does not take away the ratio of running (2) Sometimes what is added does away something in the ratio of what it is added to, as when it is said that the African is white with respect to his teeth, for specifying “teeth” does away with something of the ratio of what is called white, since a things can’t be called white unless the whole is white, or when most of its parts are, or the principal parts. If one concludes “the African is white with respect to his teeth, therefore he is white” it is sophistical, being the fallacy of secundum quid and simplicter. The cause of the apparent truth in this fallacy is the agreement of what is secundum quid and what is simpliciter, the cause of it not actually being true is the diversity of the same.

There are five modes of this fallacy.

1.) When a qualification adds an opposite to another. As in this argument

Caesar is a dead man
Therefore, he is a man.

This does not follow, since being a dead man is opposed to being a man since living is of the ratio of a man, a man being an animal and an animal being an animate, sentient substance. So clearly the qualification dead destroys the ratio of man.


He is a good thief
Therefore, he is good.

For good supposed per se is opposed to theft. Likewise this:

A liar speaks the truth by saying he speaks falsehood.
Therefore, he speaks the truth.

This does not follow since speaking the truth is opposed to speaking falsehood, and vice versa.

2.) When a qualification is added that pertains to the act of the soul.

An act of of the soul can concern both the existent and non-existent, as here

Chimera is an animal about whose existence one can have an opinion (opinabile)
Therefore, Chimera is an animal.

This does not follow since to be something “about whose existence one can have an opinion” adds to “animal” by taking away something of its ratio. Likewise this:

Caesar exists in the memory of men
Therefore, Caesar exists.

Or this:

You have happiness as an object of your will (in tua voluntate)
Therefore, you have happiness.

3.) When a qualification added signifies something existing in potency.

Like this:

An egg is potentially an animal
Therefore, it is an animal

This does not follow since being in potency takes away the ratio of what has being simpliciter.

4.) When an added qualification signifies a part.

Like this:

The African is white-toothed
Therefore, he is white.

This does not follow because existing in a part takes away the ratio of that which has being simpliciter.

Note that if some part by nature can denominate the whole this fallacy will not arise, as here:

That man has curly hair

Therefore, he is curly.

This follows fine, because the person is called a blonde by his hair. This can be extended to other parts, like those of place, time, or of other wholes. If something is added to a whole existing in a place, and the part by nature does not denominate the whole, a fallacy will arise, as in

This diet is good for the sick
Therefore, it is good

Likewise for what is a part in time, as in

Drinking wine is bad for the sick,
Therefore it is bad.

5.) When a qualification restricts the term to which it is added, which stands to it as a subject. As here

The wise man wants evil done away with
Therefore, he wants evil.

And this is for the same reason as others like it.

So clearly this fallacy arises because of the perfect and the imperfect, for that qualification takes away the ratio of something in that it signifies some imperfect being.


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