ONT Re: Determination
¤~~~~~~~~~¤~~~~~~~~~¤~~~~~~~~~¤~~~~~~~~~¤~~~~~~~~~¤
| The terms 'à priori' and 'à posteriori' in their ancient sense
| denote respectively reasoning from an antecedent to a consequent
| and from a consequent to an antecedent. Thus suppose we know that
| every incompetent general will meet with defeat. Then if we reason
| that because a given general is incompetent that he must meet with
| a defeat, we reason 'à priori'; but if we reason that because a
| general is defeated he was a bad one, we reason 'à posteriori'.
|
| Kant however uses these terms in another and derived sense. He did not
| entirely originate their modern use, for his contemporaries were already
| beginning to apply them in the same way, but he fixed their 'meaning' in
| the new application and made them household words in subsequent philosophy.
|
| If one judges that a house falls down on the testimony of his eyesight
| then it is clear that he reasons 'à posteriori' because he infers the
| fact from an effect of it on his eyes. If he judges that a house falls
| because he knows that the props have been removed he reasons 'à priori';
| yet not purely 'à priori' for his premisses were obtained from experience.
| But if he infers it from axioms innate in the constitution of the mind,
| he may be said to reason purely 'à priori'. All this had been said
| previously to Kant. I will now state how he modified the meaning
| of the terms while preserving this application of them. What is
| known from experience must be known 'à posteriori', because the
| thought is determined from without. To determine means to make
| a circumstance different from what it might have been otherwise.
| For example, a drop of rain falling on a stone determines it to
| be wet, provided the stone may have been dry before. But if the
| fact of a whole shower half an hour previous is given, then one
| drop does not determine the stone to be wet; for it would be wet,
| at any rate. Now, it is said that the results of experience are
| inferred 'à posteriori', for this reason that they are determined
| from without the mind by something not previously present to it;
| being so determined their determinants or //causes/reasons// are
| not present to the mind and of course could not be reasoned from.
| Hence, a thought determined from without by something not in
| consciousness even implicitly is inferred 'à posteriori'.
|
| Kant, accordingly, uses the term 'à posteriori' as meaning what
| is determined from without. The term 'à priori' he uses to mean
| determined from within or involved implicitly in the whole of what
| is present to consciousness (or in a conception which is the logical
| condition of what is in consciousness). The twist given to the words
| is so slight that their application remains almost exactly the same.
| If there is any change it is this. A primary belief is 'à priori'
| according to Kant; for it is determined from within. But it is not
| 'inferred' at all and therefore neither of the terms is applicable in
| their ancient sense. And yet as an explicit judgment it is inferred
| and inferred 'à priori'.
|
| CSP, CE 1, pages 245-246.
|
| Charles Sanders Peirce, "Harvard Lectures 'On the Logic of Science'", (1865),
|'Writings of Charles S. Peirce: A Chronological Edition, Volume 1, 1857-1866',
| Peirce Edition Project, Indiana University Press, Bloomington, IN, 1982.
¤~~~~~~~~~¤~~~~~~~~~¤~~~~~~~~~¤~~~~~~~~~¤~~~~~~~~~¤