Assess Kant`s Arguments For The Claim That There Are Synthetic A Priori Judgements

Kant's argument that there are synthetic a priori judgements essentially claims that judgements can be necessarily true by means other than conceptual containment and the principle of contradiction. Kant's argues this by stating the conditions for this distinct category of judgements and pointing to examples of judgements that fulfil these conditions. Whilst the analytic/synthetic distinction validly points to a difference in the way certain propositions are known, they are not known in the distinct way Kant suggests. In the examples he gives, Kant mistakes the complex conceptual analysis required to reveal non-evident analytic truths for an external synthesis.

Kant assents to the historically accepted view that propositions are known in two distinct ways - a priori and a posteriori. A posteriori knowledge is defined as contingent and empirical. It is empirical since it is experiential observations that provide evidence for these beliefs. Through sensory contact with the external world, we come to know certain facts about it. We justify these claims on the quality of experiences where content is presented to us in a certain way. Kant claims that 'experience teaches us that a thing is so and so, but not that it cannot be otherwise'. This means all a posteriori truths are subject to potential change in light of alternate experiences. Since we can conceive of them being false they are not necessarily true, but contingently true. For example, the a posteriori claim 'that book is blue' can only be contingently true, since we can imagine a case in which we would revise the claim to be false. If I were to close my eyes and then reopen them to see the same book as now red, I would regard the former claim to be false when uttered in this new context..

Kant accepts that all knowledge begins with experience. Experience is the precursor to all knowledge, providing us with the content required for constructing propositions. However, we have knowledge that does not arise out of experience, propositions whose truth or falsity is known independently of empirical observations. Kant calls knowledge of this nature a priori. A priori propositions express necessary truths where a posteriori propositions cannot since their truth does not depend on experience, which is always subject to change. The equivalent criterion for a priority, strict universality, follows if a proposition is necessarily true. If a judgement is necessarily true, it will be true for all cases to which it applies. Experience can only provide 'assumed or comparative universality through induction'. We cannot be sure there will not be an exception to the rule. A priori judgements cannot be 'falsified by experience'. Kant provides examples that fulfil these criteria. He points to mathematical judgements, such as '7+5=12' and the principle of causation - 'every alteration must have a cause'. Such truths are known without reference to particular experience and hold their truth necessarily. The idea that the addition of seven and five could equal anything other than twelve is unintelligible to us. It is true independent of experience in the sense that no experience could show it to be false. Kant takes such examples to be evidence of the existence of a priori judgements.

On the hypothesis that a priori judgements exist, Kant makes a further distinction between types of true judgement - analytic and synthetic. This distinction concerns the relationship between the predicate and subject of a judgement. A judgement is considered analytic if it fulfils two criteria - the predicate is contained in the concept of the subject and the judgement is true in virtue of the principle of contradiction. For example, 'all bachelors are unmarried'. A predicate in an analytic judgement is contained in the subject if it is one of the concepts thought to constitute the meaning of the subject. The predicate, unmarried, is a constituent concept of the subject, bachelor. Their connection is 'thought through identity'; the predicate is known to be part of the subject since it is identical to one of its constituent concepts. Analytic judgements can thus be known to be true if their negation entails a contradiction, since a subject cannot both possess and not possess a property at the same time. Analytic judgements are thus true necessarily, their truth resting purely on the meaning of the terms and the laws of logic. This restricts them to being a priori. These are contrasted with synthetic judgements. A judgement is synthetic if the predicate is connected with, but not contained within, the concept of the subject. Its truth must derive from something other than analysis of the meaning of the terms involved and the principle of contradiction. The predicate of a synthetic judgement is not a constituent concept of the subject; it is connected to it in some external manner, by other means than conceptual containment. A posteriori judgements 'are one and all synthetic'. Predicates are connected to their subject by reference to experience. They are ampliative, extending our knowledge, in that they connect a predicate to the subject not already thought in it, where analytic judgements rather clarify our concepts by revealing the subject's structure.

Kant does not just restrict syntheticity to a posteriori judgements, however, claiming that some judgements are synthetic a priori. Crucially, this implies that there exist some judgements that are necessarily true on some basis other than the principle of contradiction. He rests this claim on examples of cases where he feels such knowledge is demonstrated, pointing to maths, geometry and metaphysical claims as evidence. Take the judgement '7+5=12'. Kant argues that the concept 'the sum of seven and five' does not contain the concept 'twelve'. Some external factor is required to determine the truth of the proposition, yet it is true necessarily and independently of experience. For this to be true by the principle of contradiction, we must add some additional principle. This same reasoning is applied to geometrical truths such as 'a straight line is the shortest distance between two points'. The concept of straightness does not contain the notion of being the shortest distance between two points, Kant suggests. Some extra synthesis is required to know the truth of the judgement, yet it is known necessarily. Kant sees these as examples of necessary, a priori knowledge, where the predicate is not contained within the concept of the subject and so such judgements are true by something other than contradiction. If we are to view such judgements as cases of knowledge, we must accept the synthetic a priori exists according to Kant.

Kant's criteria for distinguishing between analytic and synthetic propositions have been criticised for various reasons. One objection is that his account of the ability of conceptual analysis to yield necessary truths assumes that concepts have determinate meanings. The process can only provide us with necessary truths about concepts if we assume all individuals define instances of a concept by the possession of the same necessary conditions. Since concepts lack this objective character, it can only reveal truths about the meaning of the concepts an individual has. However, merely testing whether a predicate is 'thought' in the concept of a subject cannot be regarded a reliable means of revealing truths about this concept, even if such truths purely concern our subjective definition. Since we are 'capable of understanding a concept without our minds immediately being led on to all its implications and components', that a predicate may not be thought in a concept does not entail that, on closer reflection, we find out that it is. As Allison puts it, we are unable to tell whether 'the failure to find one concept contained in another is due to the actual syntheticity of the judgement or to the limited insight of the person making the judgement.' This psychological misgiving means conceptual containment cannot be a reliable test for the analyticity of a concept and equally affects our ability to test for synthetic propositions on Kant's criteria.

Bennett expands on this type of criticism, claiming Kant's view that there is such a thing as synthetic a priori propositions stems from a confusion of two types of analytic a priori propositions. The crux of Kant's concern with the synthetic a priori is the issue of how certain judgements can be true a priori necessarily without being self-evident tautologies. However, as Bennett suggests, we are not required to posit the existence of a separate category of judgements in order to explain how this is the case. A proposition may be true in virtue of purely 'conceptual considerations', the meaning of the terms involved and the application of logic, whilst not being self-evident or obvious. A more thorough investigation of our concepts is required to show the truth of such judgements, however this investigation doesn't require the external factor Kant suggests. The necessity of such truths can still be explained by reference to conceptual considerations.

We can take this approach to account for the non-immediate but necessary truths of maths and geometry. Kant uses the propositions of maths and geometry as evidence for the existence of synthetic a priori judgements. Without such examples, Kant lacks a substantial basis upon which to claim the synthetic a priori exists. It is not clear whether mathematical and geometrical truths are of the nature Kant ascribes them. In line with Bennett, Ayer suggests they are non-evident analytic truths. Despite the fact that geometry and mathematics can be applied to physical objects, this should not shroud the reality that they are systems of definitions, the truth of which is defined internally. Kant suggests geometrical judgements do more than just clarify our concepts, but reveal the nature of physical space. Ayer argues that geometries are not 'about anything. But we can use geometry to reason about physical space'. Geometry is a logical system, telling us that if something can be brought under its definitions then certain implications follow necessarily. Whether geometry reflects actual relationships in the physical world is 'an empirical question which falls outside the scope of geometry itself'. Everything follows by definition once the meaning of the terms is known. Ayer suggests Kant is misled by his psychological criterion into falsely regarding mathematical judgements as synthetic. That we can understand a subject without being immediately aware of all its logical implications does not mean these implications aren't hidden in our concept. The complexity of mathematical truths does not entail that they are not true by definition; they are still reached by purely conceptual considerations. Our inability to see at a glance the implications of our definitions is a result of the 'limitations of our reason', Ayer suggests. This creates the illusion of synthesis, where really all that is occurring is a complex investigation into the logical implications of initial definitions. Thus, we see Kant has not guaranteed the synthetic a priority of the primary evidence he provides for such judgements. The judgements of maths and geometry can be explained in terms of complex systems of definitions, whose truths, while not self-evident, are reached analytically.

In his arguments for the synthetic a priori, Kant claims the existence of necessary a priori truths that are not purely tautologous. Kant highlights a difference in the way necessary a priori truths are known. Whilst some a priori judgements are evidently tautologous, a deeper process of analysis is required to reveal the truth of others. Kant mistakes the more complex process of conceptual analysis required to reveal the relationship between subject and predicate in mathematical and geometric judgements for an external synthesis. Whilst they can be applied to fundamental aspects of the external world, Kant fails to show they do not derive their truth from a system of internal definitions. Kant fails to establish that a priori truths can be known by means other than conceptual consideration, his examples being entirely explainable in these terms. The distinction he creates seems only to point to the differing degree of conceptual consideration that is required to reveal the truth of varying a priori propositions.