*verum non sequitur nisi ex vero*, i.e. truth only follows from truth.

This principle has to be severely qualified before it can even begin to pass muster. The obvious types of counterexample (‘Grass is blue, therefore grass is coloured’, ‘I have hands and a rhinoceros, therefore I have hands’) can be dismissed if he's talking about

*formal*consequences from one

*categorical*proposition to another. But even then the principle falls foul of the mediaeval insistence on the existential import of universal affirmations, which licenses the inference ‘Every man is white, therefore some man is white.’

Has anyone else come across a similar principle elsewhere?

## 10 comments:

A quibble. We should distinguish

(A) If every chimaera is a chimaera, some chimaera is a chimaera

from

(B) If some chimaera is a chimaera, some chimaera exists.

since one might reasonably agree with the categorical proposition (A) but not with the existential proposition (B), i.e. 'existential import' strictly means not (A) but (B).

Indeed, a lot of 13C scholastics (the 'intentionists') held just this view.

But this does not detract from your main point.

Just to clarify two points:

(i) since (A) and (B) are hypotheticals, I take it you're talking about the

consequentin both cases;(ii) should "some" in (B) be "every"?

If

every chimaera is Fhas existential import – that is, if (unlike universally quantified propositions in modern logic) its truth requires there to be a chimaera – isn't that enough to license the inference tosome chimaera is F?(I suspect you may be reading something different into my phrase ‘existential import’.)

Just to clarify two points:

>> (i) since (A) and (B) are hypotheticals, I take it you're talking about the consequent in both cases;

No, the whole thing.

>>(ii) should "some" in (B) be "every"?

Could be, doesn't really matter, since 'every A is B' implies 'some A is B'. The question is whether 'some A is B' implies 'Some A-which-is-B' **exists**.

>>If every chimaera is F has existential import – that is, if (unlike universally quantified propositions in modern logic) its truth requires there to be a chimaera – isn't that enough to license the inference to some chimaera is F?

Again, you need to distinguish the question of whether 'every A is B' implies 'some A is B', which it does in traditional logic, but doesn't in modern logic, from the question of whether such categorical statements imply existential statements. Definition: a categorical statement uses the word 'is' (as the copula), an existential statement uses the word 'exist' (or the verb 'is' secundum adiacens, ie. as a predicate.

>>(I suspect you may be reading something different into my phrase ‘existential import’.)

I may be, but I don't think so. I think you mean that an assertion has 'existential import' if it implies 'some A is B'. Whereas, correctly, a statement has existential import only if it implies an existential proposition. 'some A is B' is not an existential proposition (although it may imply one).

You may find this useful:

http://uk.geocities.com/frege@btinternet.com/opposition/brentanoinnovations.htm

rats, the link failed. Google

brentano's logical innovations

to get the paper in question.

On (i), you surely can't be talking about the whole thing when you say "the categorical proposition (A)", because (A) is not a categorical proposition. It's a hypothetical proposition, that is, a proposition formed from two or more categorical propositions. (At least, so I understand from Shirewood, Burley, Ockham and Buridan.) Hence my suggestion that you were instead talking about the consequents.

In any case, I now see what you're saying. I must say it had never occurred to me that 'some A is B' might not have existential import. Thanks for the article, which I'll be sure to read. (By the way, is anyone bothered by the fact that e.g. 'some man is white' is barely English? Plurals are fine. But the nearest we get to 'some man' is in e.g. 'some guy told me', where it seems to be a variant of 'someone'.)

From a corner of my mind the name Fred Sommers emerges. I'd be interested to hear what you think of him.

Sorry, I did indeed write

>> with the categorical proposition (A) but not with the existential proposition (B),

meaning of course, the categorical proposition *in* A. I.e. the consequent, as you say.

>> Hence my suggestion that you were instead talking about the consequents.

As indeed I was, sorry.

>>By the way, is anyone bothered by the fact that e.g. 'some man is white' is barely English?

Well there's a lot of English 'translation' of medieval Latin that is barely English. You try and translate in a way that is intelligible, but then you are faced with the problem that the Latin often reflects how they actually *thought*, and so you leave it in a barely intelligible state.

In any case, we do say things like 'some guy is on the phone'.

>>From a corner of my mind the name Fred Sommers emerges. I'd be interested to hear what you think of him.

Quite obviously he was a strong influence.

Other bits and pieces. I got your message on 'Hello World' which I stupidly replied to, despite it is a no reply thing. In summary, thanks for the material which I am reading with interest, and will provide hours of amusement. I've already started on Distinction 8 which is about essence and existence. In fact, there is something truly interesting there because on p. 891 (p. 422 in the pdf) you come across the sentence 'Praeterea, non debet poni superfluum aut aliqua distinctio sine causa, quia frustra fit per plura quod potest fieri per pauciora'. The last phrase (beginning 'frustra') is one of Ockham's famous formulations of 'Ockham's razor'. Note that he never actually said 'entities should not be multiplied beyond &c'. Here, Auriol is giving an identical formulation. But it may be a Franciscan expression, and I think Scotus used it.

On the other piece you sent me, you haven't given me much time to look at it, but I'll try. I've already read it through – note future contingents is not my area at all, but I'll give it a try.

the north face outletmoncler coatlouis vuitton outlet storescheap uggsray ban sunglassestoms shoes ukgucci outlet onlinekate spadekate spade outletadidas yeezymichael kors bagsnfl jerseys wholesalemichael kors outlet onlinepandora charmshermes bagsadidas outlet storeretro jordans 13true religion outletair jordan shoesuggs salechristian louboutin pas cherbeats by dremichael kors canada outletrolex watches outletmichael kors outlet clearancemichael kors handbagslongchamp outletray ban sunglasses outletlouis vuitton handbagsfitflop shoesadidas originals storegucci handbagsburberry handbagsfitflop sandalsugg outletlouis vuitton pursesabercrombie & fitch outletasics shoes for womenfitflops saleugg sale20168.10chenjinyan

Coach OutletCoach OutletCoach Outlet OnlineCoach Factory OutletCoach OutletCoach Outlet StoreJordan Shoes For SaleAir Jordan 11Air Jordan 1Cheap JordansArticles that are very interesting to read, hopefully provide benefits for many people

Obat Alami Atasi Sesak Nafas

Pengobatan Tuntaskan Penyakit Kudis

Bahaya Dan Cara Mengobati Ginjal Bocor

Pengobatan Atasi Dislokasi Sendi

Pengobatan Alternatif Untuk Mengangkat Miom

Pengobatan Untuk Mengatasi Tukak Lambung

Banyak sekali situs-situs yang membahas tentang

menggugurkan kandungandengan tujuan untuk mencegah kehamilan . Namun untuk kasus tertentu seperti darurat medis yang bisa membahayakan ibu hamil maupun janinnya atau korban perkosaan cara menggugurkan kehamilan boleh dilakukan . Tetapi yang perlu di ingatcara menggugurkan kandungan secara alamiseperti menggunakan nanas muda maupun pepaya muda atau bahan alami lainnya sangat tidak di anjurkan . Ternyatamimpi basahtidak hanya dialami oleh kaum pria saja , wanita juga mengalaminya . Bagi para suami sangat penting sekali untuk mengetahuicara membuat wanita cepat keluardalam melakukan hubungan intim . Dalam satu bulansiklus menstruasipada setiap wanita berbeda-beda , bisa saja terjadi antara 23-35 hari , namun rata-rata siklus haid wanita adalah 28 hariPost a comment