Why is synthetic a priori knowledge important

No additional experience is needed. If S has the experiences needed to acquire the concepts of bachelorhood and untidiness, acquires these concepts, and understands 7 , S will not have a justification to believe 7 —even if we suppose, for the moment, that all bachelors are untidy. S would have to observe many bachelors and their personal habits, or be told about the personal habits of bachelors by others for 7 to be justified.

So far we have only a negative account of a priori justification; it is justification that does not depend on experiences beyond those necessary for understanding. But in virtue of what could S be justified in believing something apart from experience? The standard answer appeals to the special nature of the propositions that can be a priori justified: they are supposed to be self-evident. This definition of self-evidence may not be entirely satisfactory. One seeking a positive, informative account of how S could be justified in believing P simply in virtue of the fact that S understands P should not be satisfied when told that P is a special, self-evident proposition, when all this means is that P is justified to a high degree for everyone who understands it.

Nevertheless, the lack of an explanation of the mechanism that brings something about is not a decisive reason for thinking it could not come about. We shall assume that SE correctly defines self-evidence. We have not yet addressed the connection between self-evidence and truth, but this is not the problem: self-evidence is taken to imply truth.

To explain why S could understand and believe P SE but fail to know P SE , it will be helpful to distinguish between propositional justification and doxastic justification. We introduce the distinction in terms of having good reasons, but it can be generalized to other ways of being justified.

If S has good reasons for believing a proposition, P , e. Note that P might be propositionally justified for S even though S does not believe P —while S knows propositions that entail P , the proposition P might never have even occurred to S.

This entails that she has no pet hippopotamus, so this proposition is propositionally justified for S. But unless S is a little odd, this is not a proposition S currently believes. Significantly, doxastic justification requires more than propositional justification plus belief. Knowledge requires basing the belief in the proposition on something that justifies it. This goes for moral knowledge of self-evident moral propositions as well as it goes for any other kind of knowledge. So far, the standard view may understand the class of a priori propositions too narrowly.

Mathematics and logic are regarded as the paradigm a priori disciplines. But it is doubtful that all the mathematical and logical truths we know are self-evident. Many of these truths require proof. The standard view can extend the class of a priori propositions without compromising its basic approach by adding that if S believes P on the basis of proving it from self-evident premises by steps that are self-evidently valid, then S is a priori justified in believing P.

To sum up, the standard view holds that a priori knowledge is justified independently of experience, where this means experience beyond the experience required to understand the relevant proposition.

There are certain special, self-evident propositions that are propositionally justified for any person who understands them. If a person believes a self-evident proposition solely on the basis of understanding it, the person will be doxastically justified in believing it. Such propositions are often referred to as a priori , which should be taken to mean that it is possible for one to be a priori justified in believing them.

By extension, propositions are also a priori if they can be deduced from self-evident premises via steps that are self-evidently valid. A person who believes such a proposition on the basis of such a proof will be a priori justified in believing it. It is also possible to be empirically justified in believing an a priori proposition, but one cannot be a priori justified in believing empirical propositions.

Before closing the presentation of the standard view, we should highlight a potential problem already implicit in our presentation. As we stressed, the basic concept of a priori justification is of justification that is independent of experience. The standard view recognizes that one typically needs experience to understand a proposition, and interprets experience independent justification as justification that requires no additional experience.

But consider an experience like this. You do not know for yourself. What happens in such cases? Understanding alone does not seem to justify you in believing. But whatever it is called, it is hard to deny it is an experience. So the standard view faces a problem: there is a distinctive kind of experience apparently required for a priori justification in believing, and hence, a priori knowledge of, some propositions typically regarded as a priori and perhaps even self-evident.

Those who take the standard view might respond by accepting that rational intuition is an experience and distinguishing this experience from the experiences that are involved in empirical justification, i.

This modified standard view could then maintain that a priori knowledge and justification are independent of the latter experiences, but not necessarily all experience; a priori justification can be grounded in an experience of rational intuition—perhaps it is always so grounded.

Thus, on the modified standard view, the special role of understanding comes down to this: understanding an a priori proposition is the only prerequisite for rational insight into its truth; understanding the proposition does not guarantee that one will attain such insight, but it is the only thing that is necessary.

Notice, on this modified standard view, self-evident propositions no longer play such a prominent role. It is not an essential part of the view that there are special propositions, and anyone who understands one of these propositions has propositional justification.

If one wants to think in terms of special propositions, there will be propositions that are special only in an attenuated sense: it is possible for a person to have the experience of seeing the propositions to be true simply by understanding and thinking about them.

Some might consider this modification too much of a departure from the spirit of the standard view. While it is not beyond criticism, we will proceed assuming the standard view about a priori knowledge and justification is true. On one view, being a bachelor is a complex concept that is composed of being unmarried as well as being an adult male. Hence, part of thinking of someone as a bachelor is thinking of him as unmarried.

Compare this with the synthetic proposition 7 , that all bachelors are untidy. The concept of being a bachelor is not partly composed of the concept of being untidy. Thinking of someone as untidy is not part of thinking of him as a bachelor.

A more contemporary understanding holds that sentences are analytic just in case they can be converted into logical truths by replacing terms with terms that have equivalent meanings Frege []. One might be tempted to think that all and only propositions expressed by analytic sentences can have a priori justification, and that propositions expressed by synthetic sentences can only have a posteriori justification.

We should resist this temptation. A number of philosophers, beginning with Kant, have claimed that some synthetic propositions can have a priori justification. As we will discuss below, Kant thought that all moral propositions were synthetic but could be established only by reason. Moreover, if one considers what is fundamental to the two distinctions, there is no obvious reason to assume they would perfectly coincide. Two such fundamentally different distinctions could coincide, but it is not immediately apparent that they do; it would take considerable work to show that they do.

We can divide metaethical positions into two kinds: cognitivist and non-cognitivist. Cognitivists maintain that when one sincerely makes a moral statement in an ordinary context, one believes the proposition expressed by the statement.

The early non-cognitivists A. Ayer and R. Hare maintained that moral statements were akin to utterances a and b respectively, that is, they express either emotive reactions or commands. Other forms of non-cognitivism propose different accounts of exactly what one does when one makes a moral statement see entry on moral cognitivism vs.

Since non-cognitivism holds that we do not express beliefs when we make moral statements, there is no reason for non-cognitivists to think that there are any moral beliefs—according to non-cognitivism, even though moral statements typically have the form of declarative sentences, there are no moral propositions that correspond to them.

If there are no moral beliefs or propositions, there is no a priori moral justification or a priori moral knowledge. So, the question of whether some moral propositions can be justified a priori really comes up only in the context of cognitivism. However, many non-cognitivists want to vindicate as much of actual moral thought and practice as possible, particularly quasi-realists such as Simon Blackburn and Alan Gibbard While denying that there are, strictly speaking, moral propositions that are true or false or moral beliefs, or moral arguments that are valid or invalid , they would at the same time maintain that in the moral realm there are things close enough to propositions, truth, belief, and validity that our practice of speaking of such things as moral beliefs and these beliefs being true or false makes sense.

And such theorists would certainly want to allow that moral beliefs can be better or worse in a way that closely corresponds to beliefs being more or less epistemically justified, strictly understood.

So there are interesting questions about whether there is something closely akin to a priori moral justification and knowledge on these views. But in this entry we will limit ourselves to cognitivist theories.

Moreover, serious questions regarding a priori moral knowledge and justification arise only for non-error-theoretic versions of cognitivism. Error theories, such as J. Moral propositions are systematically false because they presuppose something radically mistaken. Mackie claims they presuppose the existence of objectively prescriptive moral facts, when there are no such facts Ch.

A person could be justified in believing a false proposition, but one could not know it. And it is difficult to see how one could even be justified a priori in believing a proposition of a type that is systematically false because it makes a radically mistaken presupposition.

Thus, this entry focuses on non-error-theoretic versions of cognitivism. Having discussed some metaethical theories such as cognitivism and non-cognitivism, we should pause to distinguish claims regarding a priori knowledge or justification of moral evaluations from claims regarding a priori knowledge or justification of meta-ethical propositions, such as that moral statements do not express propositions. Much meta-ethical theorizing is presented as an analysis of moral language, and it seems likely that those involved think of themselves as conducting an a priori inquiry.

It would be interesting to devote more specific attention to a priori meta-ethical epistemology, but we are concerned mostly with a priori knowledge or justification of moral propositions. We focus almost exclusively on moral theories from the 20 th century and later; the exception is Kant, with whom we begin. After briefly discussing Kant, we move on to the non-naturalist moral theories presented in the early part of the 20 th century by Moore and Ross.

We then consider naturalist moral theories developed much later in the 20 th century, and close by considering particularism and more recent versions of intuitionism that are descendants of the positions developed by Moore and Ross.

For Kant, there is a close connection between the nature of moral truths—in particular, their prescriptive content i. In his view, one can discover a maximally general, fundamental moral principle. He held that we could then deduce more specific, but still general moral truths from this fundamental principle. Kant provides various formulations of the categorical imperative, the first being that one ought to act only in accordance with a maxim [ 3 ] that one can at the same time will to become a universal law—roughly, an act ought to be done by someone only if the person could will, without contradiction, that everyone act as he or she is acting.

Examples of more specific principles he deduces from the categorical imperative are that one ought not make lying promises or commit suicide. To apply the categorical imperative, the person must consider what would happen if everyone in some difficulty made a lying promise to escape.

If so many lying promises were made, no one would believe a person who promised to do something, so under these conditions one could not escape a difficulty by making a promise. Hence, the person could not consistently will that his maxim be a universal law, since making it a universal law would frustrate his aim in making the lying promise. Therefore, one ought not escape a difficulty by making a lying promise.

In Book II of the Groundwork [] Kant claims the fundamental moral truths are synthetic a priori because moral truths are prescriptive. Kant held that the categorical imperative is not analytic, because although Kant thought the applicability of the categorical imperative to any given individual is deducible from the assumption that the individual is rational, the concept of the categorical imperative is not contained in the concept of a rational being.

Kant thought the categorical imperative must be discovered a priori —through reason—because, as a fundamental moral law applying to all rational beings, it cannot be discovered through mere experience: one cannot learn how one should act from how people do act. Moreover, we can see why Kant may have thought that the necessity and universality of moral truths makes them impossible to discover a posteriori.

Regarding necessity: observing how things actually go seems insufficient to find out how they must go. And regarding universality: if moral truths are universal in the sense that they are true in all contexts, then one could only verify the truth of a moral claim by a experiencing all contexts and b perceiving the moral truth in each one. But that is clearly impossible.

Thus, on a standard reading of Book II, the prescriptive content of moral claims, along with their necessity and universality, led Kant to believe we know moral truths only a priori. However, some interpret Kant as saying that if a moral truth is a priori , then it must also be necessary and universal Dancy Moreover, if P is necessary, then P must also be universal; for if P must be true, then it is true in every actual case.

As we will see, moral particularists deny there is any such relationship between the content of moral claims and the means by which we know them. Particularists claim that we can have a priori moral knowledge, even though all moral truths are contingent and particular. How, specifically, does Kant think that one can establish the categorical imperative a priori? The crucial premise is that practically rational beings are autonomous, in the sense that their wills can be determined by rules they give themselves.

Kant holds that the law that an autonomous agent gives to herself must tell her which ends to pursue and not merely which means to employ in light of the ends the agent already has.

Kant therefore rejects the more orthodox conception of practical reason as purely instrumental, i. This leads Kant to the categorical imperative, roughly: for an agent to perform a moral action, the maxim the agent acts on must be one that the agent can consistently will to govern everyone, regardless of their goals, as a necessary law. Moore reacted against views that provided naturalistic definitions of moral concepts, especially that of goodness see entries on naturalism , and moral naturalism.

According to such views, fundamental moral principles are analytic, and hence knowable a priori. Since the fundamental principles defined moral concepts in natural terms, one can infer whether some specific thing is good or action right from the principle conjoined with appropriate propositions about the natural properties of the thing or action, the latter being knowable empirically.

Consider a definable term: a triangle is a closed plane figure with three angles. But the question is open; it is perfectly reasonable. One might, e. Hence, Moore would conclude, the analysis fails. He concluded that goodness is non-natural see entry on moral non-naturalism. Superficially, his view seems to comport well with the standard conception of a priori knowledge. But consider how he explains his position, quoted here at some length:.

But I am anxious that this expression should not be misunderstood. The expression does not mean that the proposition is true, because it is evident to you or me or all mankind, because in other words it appears to us to be true. That a proposition appears to be true can never be a valid argument that true it really is. By saying that a proposition is self-evident, we mean emphatically that its appearing so to us, is not the reason why it is true: for we mean that it has absolutely no reason.

It would not be a self-evident proposition, if we could say of it: I cannot think otherwise and therefore it is true. For then its evidence or proof would not lie in itself, but in something else, namely our conviction of it. That it appears true to us may indeed be the cause of our asserting it, or the reason why we think and say that it is true: but a reason in this sense is something utterly different from a logical reason, or reason why something is true.

Moreover, it is obviously not a reason of the same thing. The evidence of a proposition to us is only a reason for our holding it to be true; whereas a logical reason, or reason in the sense in which self-evident propositions have no reason, is a reason why the proposition itself must be true, not why we hold it so to be.

Again, that a proposition is evident to us may not only be the reason why we do think or affirm it, it may even be a reason why we ought to think it or affirm it. But a reason, in this sense too, is not a logical reason for the truth of the proposition, though it is a logical reason for the rightness of holding the proposition…. My Intuition of its falsehood is indeed my reason for holding and declaring it untrue; it is indeed the only valid reason for so doing.

But that is just because there is no logical reason for it; because there is no proper evidence or reason of its falsehood except for itself alone. It is untrue, because it is untrue, and there is no other reason: but I declare it untrue, because its untruth is evident to me, and I hold that that is a sufficient reason for my assertion. We must not therefore look on Intuition, as if it were an alternative to reasoning.

Nothing whatever can take the place of reasons for the truth of any proposition: intuition can only furnish a reason for holding any proposition to be true: this however it must do when any proposition is self-evident, when, in fact, there are no reasons which prove its truth. Nothing obviously follows about the epistemic status of such propositions or about beliefs in such propositions.

Second, given his conception of self-evidence, Moore chooses an odd example of a self-evident proposition. For that pleasure is not the only good seems to follow from various propositions regarding what things are good, propositions that Moore accepted—and that are apparently self-evident—e.

Finally, to interpret Moore as holding that we are a priori justified in accepting fundamental moral principles, one must adopt the modified standard view. And his position nicely illustrates the problem that forces the modification of the standard view.

Moore held that what justifies one in believing a fundamental moral principle is that the principle is self-evident and that it appears to be true, i. Hence, to regard this justification as a priori , one must make an exception for this specific kind of experience. While Moore famously denied hedonism, this was because he denied that pleasure is the only good. Presumably one must experience pleasure to acquire the concept of pleasure.

But then how exactly is it that one is justified in believing that pleasure is good? Is it that once one has the concepts of pleasure and goodness, one believes that pleasure is good simply on the basis of understanding this proposition? Or is it that once one understands this proposition, one has a rational intuition of its truth?

Or is it instead that when one experiences pleasure one also experiences its goodness? If something like the latter, the justification for our belief that pleasure is good seems more empirical than a priori. Kant viewed moral knowledge as fundamentally a priori in the sense that moral knowledge must be the result of careful reasoning first transcendental, then deductive ; one could discover through reason the fundamental moral principle, and then deduce from that principle more specific moral duties.

Moore, on the other hand, explicitly rules out reasoning to fundamental moral principles; since these principles are self-evident, Moore denies that there are, properly speaking, any reasons for them. Moore did not hold that all moral knowledge is intuitive. In the Principia he maintained that the utilitarian principle was analytic, hence, knowledge of this principle would not require a special intuition.

However , since Moore held that one ought to do what produces the most good, one would have to engage in empirical investigation of the consequences of various types of action to determine what one is obligated to do. A more interesting reason why Moore did not hold that all moral knowledge results from direct intuition was that he denied that intuition is infallible. On his view, it can appear to one that a false moral proposition is self-evidently true.

One resolves any conflicts among the moral principles one intuits—e. Ross is for many the paradigm intuitionist see entry on William David Ross. He held both pluralism:. Ross provided principles specifying various grounds of duty by using the concept of prima facie duty.

Ross thought of prima facie duty as a tendency to be a duty, not as a kind of duty. He held that we have prima facie duties to keep promises and tell the truth, to provide reparation for harms we have done, to perform acts of gratitude, to insure just distributions, to benefit others, to improve ourselves, and not to harm others. He held that an act is a prima facie duty in virtue of some one component of its nature, e.

The proposition cannot be a posteriori because of this reasoning and must be, in conclusion a priori. It provides the essential bridge between rationalist and empiricist epistemology and in doing so gives probably the best account for the plausibility of metaphysical knowledge that sceptics like Hume had repudiated. Excuse the lack of proper referencing, I had formatting issues converting from Word. Feigl, H. Twentieth Century Philosophy. Gardner, S. Routledge: London. Hume, D. Oxford University Press: Oxford.

Johnson, O. Kant, I. Norman Kemp Smith Palgrave Macmillan. Nietzsche, F. Penguin Classics. Russell, B. Oxford Paperbacks: Oxford. Thanks for sharing. Hume and Kant are two of my favorite philosophers. Like Like. No problem. I think to some extent a lot of later epistemology and metaphysics has to be looked at as a response to Kant and I suppose therefore Hume! Also great, concise video. Like Liked by 1 person.

I am aware of the hugeness of the required exposition of the ideas that would be exhaustive. Johnson is not a common philosopher, it would have been better to write a brief of his biography in order to give your paper more value.

You are commenting using your WordPress. Of the Distinction between Analytical and Synthetical judgments in general. But whatever be their origin, or their logical form, there is a distinction in judgments, as to their content, according to which they are either merely explicative, adding nothing to the content of the cognition, or expansive, increasing the given cognition: the former may be called analytical, the latter synthetical, judgments.

Analytical judgments express nothing in the predicate but what has been already actually thought in the concept of the subject, though not so distinctly or with the same full consciousness. When I say: All bodies are extended, I have not amplified in the least my concept of body, but have only analyzed it, as extension was really thought to belong to that concept before the judgment was made, though it was not expressed, this judgment is therefore analytical.

On the contrary, this judgment, All bodies have weight, contains in its predicate something not actually thought in the general concept of the body; it amplifies my knowledge by adding something to my concept, and must therefore be called synthetical. For the predicate of an affirmative analytical judgment is already contained in the concept of the subject, of which it cannot be denied without contradiction.

In the same way its opposite is necessarily denied of the subject in an analytical, but negative, judgment, by the same law of contradiction. Such is the nature of the judgments: all bodies are extended, and no bodies are unextended i. For this very reason all analytical judgments are a priori even when the concepts are empirical, as, for example, Gold is a yellow metal; for to know this I require no experience beyond my concept of gold as a yellow metal: it is, in fact, the very concept, and I need only analyze it, without looking beyond it elsewhere.

Synthetical judgments require a different Principle from the Law of Contradiction. Yet they both agree in this, that they cannot possibly spring from the principle of analysis, viz. I shall first classify synthetical judgments. Empirical judgments are always synthetical. For it would be absurd to base an analytical judgment on experience, as our concept suffices for the purpose without requiring any testimony from experience.

That body is extended, is a judgment established a priori, and not an empirical judgment. For before appealing to experience, we already have all the conditions of the judgment in the concept, from which we have but to elicit the predicate according to the law of contradiction, and thereby to become conscious of the necessity of the judgment, which experience could not even teach us. Mathematical judgments are all synthetical.