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12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective

[a priori knowledge is the product of individual minds-]

7 ideas
The mind cannot produce simple ideas [Locke]
     Full Idea: The mind has no power to produce any simple idea.
     From: John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.31.02)
     A reaction: These must all come from experience, implying to common empirical view (spelled out better by Hume) that that a priori concerns only combinations of ideas which we already possess. The 'conceptual' notion of a priori is consistent with this.
A priori the understanding can only anticipate possible experiences [Kant]
     Full Idea: The understanding can never accomplish a priori anything more than to anticipate the form of a possible experience in general.
     From: Immanuel Kant (Critique of Pure Reason [1781], B303/A246)
     A reaction: This is why many people think that Kant brough metaphysical (ontological) speculation to an end. He asserts that synthetic a priori knowledge is possible, but then imposes a huge limitation on it.
A priori intuition of objects is only possible by containing the form of my sensibility [Kant]
     Full Idea: The only way for my intuition to precede the reality of the object and take place as knowledge a priori is if it contains nothing else than the form of sensibility which in me as subject precedes all real impressions through which I'm affected by objects.
     From: Immanuel Kant (Prolegomena to Any Future Metaphysic [1781], 283)
     A reaction: This may be the single most famous idea in Kant. I'm not really a Kantian, but this is a powerful idea, the culmination of Descartes' proposal to start philosophy by looking at ourselves. No subsequent thinking can ignore the idea.
Logic is a priori because we cannot think illogically [Wittgenstein]
     Full Idea: That logic is a priori consists in the fact that we cannot think illogically.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.4731), quoted by Robin Jeshion - Frege's Notion of Self-Evidence 4
     A reaction: A rather startling claim. Presumably we have to say that when we draw a stupid inference, then we weren't really 'thinking'?
We have some self-knowledge a priori, such as knowledge of our own existence [Kitcher]
     Full Idea: One can make a powerful case for supposing that some self-knowledge is a priori. At most, if not all, of our waking moments, each of us knows of herself that she exists.
     From: Philip Kitcher (The Nature of Mathematical Knowledge [1984], 01.6)
     A reaction: This is a begrudging concession from a strong opponent to the whole notion of a priori knowledge. I suppose if you ask 'what can be known by thought alone?' then truths about thought ought to be fairly good initial candidates.
A priori knowledge (e.g. classical logic) may derive from the innate structure of our minds [Horwich]
     Full Idea: One potential source of a priori knowledge is the innate structure of our minds. We might, for example, have an a priori commitment to classical logic.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §11)
     A reaction: Horwich points out that to be knowledge it must also say that we ought to believe it. I'm wondering whether if we divided the whole territory of the a priori up into intuitions and then coherent justifications, the whole problem would go away.
Maybe imagination is the source of a priori justification [Casullo]
     Full Idea: Some maintain that experiments in imagination are the source of a priori justification.
     From: Albert Casullo (A priori/A posteriori [1992], p.1)
     A reaction: What else could assessments of possibility and necessity be based on except imagination?