Innate Ideas and the Analytic/Synthetic - Priori/Posteriori propositions

Posted by Ali Reda | Posted in | Posted on 11/27/2014

In his Meno, Plato raises the epistemological question of how is it that humans have certain ideas which are not conclusively derivable from their environments? Plato argued that, as the body is from the material world, the soul is from the world of ideas and is thus immortal. He believed the soul was temporarily united with the body and would only be separated at death, when it would return to the world of Forms. Since the soul does not exist in time and space, as the body does, it can access universal truths.


Descartes and other philosophers of rationalism stressed the primacy of innate ideas placed in the human mind by God at birth. Besides mathematical principles and simple ideas, the main innate idea for Descartes was the idea of God, an idea that could not be derived from experience. Although there is obvious variation among individual human beings due to cultural, linguistic, and era-specific influences, innate ideas are thus said to belong to a more fundamental level of human cognition because they are common to everyone (Universal Assent). Descartes posited relation between mind and body is called Cartesian dualism. He held that mind was distinct from matter, but could influence matter. The mind exerted control over the brain via the pineal gland and that the soul was the place in which all our thoughts are formed.


British Empiricists, were critical of this theory and denied the existence of any innate ideas, arguing that all human knowledge was founded on experience, rather than a priori reasoning. Locke, who proposed the notion of tabula rasa (Mind as a blank slate) saw no evidence of pre-existing ideas in the mind. Locke further objected that accepting the notion of innate ideas would open the door to dogmatic assertions, as it implied that the mind was born somewhat predetermined to think based on these ideas. Accepting the existence of innate ideas could thus lead to abuse in the search for truth as well as in human affairs. Locke goes on to suggest that in fact there is no universal assent. Even a phrase such as, "What is, is," is not universally assented to; infants and severely handicapped adults do not generally acknowledge this truism. Locke also attacks the notion that an innate idea can be imprinted on the mind without the owner realizing it. Locke would not accept the idea that someone can be aware of what he or she does not know.


Leibniz acknowledged the need for a middle road between the two extremes, for him, rational ideas were virtually in the mind at birth and needed to be activated by experience, a position that builds upon Aristotle’s ideas. From this perspective, the pre-existence of a mental design is compatible with the essential need for experience. Leibniz’s New Essays on Human Understanding (1695–1705, published in 1765) was a response to Locke’s An Essay Concerning Human Understanding (1690). Leibniz suggested that people are born with certain innate ideas. The rich sense of “ self ” structured as containing the fundamental notions (innate ideas) of "being, substance, unity, possibility, change, action, and so on". They are the ingredients of our self (hence “ we are innate to ourselves ” in this sense, too). The most identifiable of these being mathematical truisms. The idea that 1 + 1 = 2 is evident to people without the necessity for empirical evidence. Leibniz argues that empiricism can only show that concepts are true in the present; if one sees one stick and then another, he knows that in that instance, and in that instance only, one and another equals two. If, however, people wish to suggest that one and another will always equal two, they require an innate idea, as they are talking about things they have not yet witnessed (No experinece yet). Leibniz called this innate ideas, "necessary truths." Another example of such may be the phrase, "what is, is," or "it is impossible for the same thing to be and not to be." Leibniz argues that such truisms are universally assented to (acknowledged by all to be true) and, this being the case, it must be due to their status as innate ideas. Often there are ideas that are acknowledged as necessarily true, but are not universally assented to. Leibniz would suggest that this is simply because the person in question has not become aware of the innate idea, not because he or she does not possess it. Leibniz argues that empirical evidence can serve to bring to the surface certain principles that are already innately embedded in the mind. This is rather like needing to hear only the first few notes of a song in order to recall the rest of the melody.


Kant introduecd two distinctions, the first was Analytic and Synthetic propositions:
  1. Analytic proposition: a proposition whose predicate concept is contained in its subject concept, we require only analysis of the subject itself to understand this proposition (True by virtue of Meaning and if true then it is self evident) - "All bachelors are unmarried".
  2. Synthetic proposition: a proposition whose predicate concept is not contained in its subject concept, we require something outside of the analysis of the subject. (True by how their meaning relates to the world and if true then it tells us something new about the world) - "All bachelors are happy"
Kant contrasts this distinction with another one which is a priori and a posteriori propositions:
  1. A priori proposition: a proposition whose justification does not rely upon experience. Therefore, it is logically necessary.
  2. A posteriori proposition: a proposition whose justification does rely upon experience. Therefore, it is logically contingent.
Of course, as Kant would grant, experience is required to understand the concepts "bachelor," "unmarried," "7", "+" and so forth. However, the a priori/a posteriori distinction as employed here by Kant refers not to the origins of the concepts but to the justification of the propositions. Once we have the concepts, experience is no longer necessary. The analytic/synthetic distinction and the a priori/a posteriori distinction together yield four types of propositions:
  1. Analytic a priori
  2. Synthetic a priori
  3. Analytic a posteriori
  4. Synthetic a posteriori
We can know analytic propositions by consulting our concepts in order to determine that they are true. Analysis of the subjects by our kowledge of concepts through previous experience. Kant says the Analytic a posteriori propositions is self-contradictory, so there are no analytic a posteriori propositions. So all analytic propositions are a priori. We can know Synthetic a posteriori by experience of the world. That leaves only the question of how knowledge of synthetic a priori propositions is possible. How understanding a proposition requires something outside of the analysis of the subject yet its justification doesn't rely upon experience.

This question is exceedingly important, Kant maintains, because all important metaphysical knowledge is of synthetic a priori propositions. If it is impossible to determine which synthetic a priori propositions are true, he argues, then metaphysics as a discipline is impossible. Before Kant's first Critique, empiricists and rationalists assumed that all synthetic statements required experience to be known. Hume's skepticism rested on that basic principles such as causality cannot be derived from sense experience only: experience shows only that one event regularly succeeds another, not that it is caused by it.  Kant's goal was to find some way to derive cause and effect without relying on empirical knowledge. Kant rejects analytical methods for this, arguing that analytic reasoning cannot tell us anything that is not already self-evident. Instead, Kant argued that it would be necessary to use synthetic reasoning. It can't be Synthetic a posteriori because this is the core of Hume scepticsm is that he found out there is no justification for causality in experienece. So it must be Synthetic a priori. However, this posed a new problem — how is it possible to have synthetic knowledge that is not based on empirical observation — that is, how are synthetic a priori truths possible?

Kant uses the classical example of 7 + 5 = 12. No amount of analysis will find 12 in either 7 or 5. The concept "12" is not contained within the concept "5," or the concept "7," or the concept "+." And the concept "straight line" is not contained within the concept "the shortest distance between two points". (So it is a synthetic) but once we have grasped the concepts of addition, subtraction or the functions of basic arithmetic which govern the relation, the same principle applies to other numerals (for example 4+6 = 10) and it tells us something new about the world without having experience with 4, 6 or 10. It is self-evident, and undeniably a priori, but at the same time it is synthetic. And so Kant proves a proposition can be synthetic and known a priori. But not all synthetic propositions are a priori, for example "All bachelors are happy" has no concepts of rules to govern the relation so it always requires experience.

Kant concluded that the mind operates through a priori categories present independently from experience. However, for him, these categories are not  innate ideas but they are merely the way the human mind necessarily processes information (for example, the concepts of substance, causality, etc.). First they would remain entirely empty unless filled with experience gathered from the senses. They give no information whatsoever to what reality really is (the things-in-themselves), but merely indicate how one understands it with a limited, human understanding. (Condition for understanding).

Thus causality when thought as a synthetic priori, it is a concept governing the events happening in sequence which we can apply at other sequences of events to tell something new about the world each time, yet they are a priori whose justification does not rely upon experience. thus Causality doesn't require experience.

Kant created a revolutionary synthesis between rationalism and empiricism that shed an entirely new light on the question of innate ideas.
  1. From rationalism, he draws the idea that pure reason is capable of significant knowledge but argues that pure reason is flawed when it goes beyond its limits and claims to know those things that are necessarily beyond the realm of all possible experience: the existence of God, free will, and the immortality of the human soul. Kant referred to these objects as "The Thing in Itself" and goes on to argue that their status as objects beyond all possible experience by definition means we cannot know them and in the Critique of Pure Reason famously showed how all arguments for the existence of God are flawed, that the received views about the simplicity and immortality of the soul were problematic, and that our freedom could never be cognized. Yet, all is not lost, for Kant believed that the existence of God, the immortality of the soul, and the freedom of the will must be considered as postulates of morality and not objects of knowledge. It follows that problems which according to Kant are beyond experience cannot even be raised by pure reason.
  2. Kant noted the peculiarity of Locke's suggesting that, after deriving all concepts from experience and reflection on experience, he could demonstrate the existence of God and the immortality of the soul, matters lying well beyond all experience. So to the empiricist he argued that while it is correct that experience is fundamentally necessary for human knowledge, reason is necessary for processing that experience into coherent thought. He therefore concludes that both reason and experience are necessary for human knowledge. In the same way, Kant also argued that it was wrong to regard thought as mere analysis. In Kant's views, a priori concepts do exist, but if they are to lead to the amplification of knowledge, they must be brought into relation with empirical data, without the concepts, intuitions are nondescript; without the intuitions, concepts are meaningless."
By locating the answers to metaphysical questions not in the external world but in a critique of human reason, Kant provides clear boundaries for metaphysical speculation and maintains a sensible, empirical approach to our knowledge of the external world. Knowledge does not depend so much on the object of knowledge as on the capacity of the knower.

Frege and Carnap

Frege's notion of analyticity included the idea of substitution of synonymous terms. "All bachelors are unmarried" can be expanded out with the formal definition of bachelor as "unmarried man" to form "All unmarried men are unmarried," which is recognizable as tautologous and therefore analytic from its logical form: any statement of the form "All X that are (F and G) are F". This expanded idea of analyticity was able to show that all Kant's examples of arithmetical and geometrical truths are analytical a priori truths and not synthetic a priori truths. Carnap said in his autobiography that:

Since empiricism had always asserted that all knowledge is based on experience, this assertion had to include knowledge in mathematics. On the other hand, we believed that with respect to this problem the rationalists had been right in rejecting the old empiricist view that the truth of "2+2=4" is contingent on the observation of facts, a view that would lead to the unacceptable consequence that an arithmetical statement might possibly be refuted tomorrow by new experiences. Our solution, based upon Wittgenstein's conception, consisted in asserting the thesis of empiricism only for factual truth. By contrast, the truths of logic and mathematics are not in need of confirmation by observations, because they do not state anything about the world of facts, they hold for any possible combination of facts.

A proposition that is necessarily true is one whose negation is self-contradictory (thus, it is said to be true in every possible world). By contrast, a proposition that is contingently true is one whose negation is not self-contradictory (thus, it is said that it is not true in every possible world). As Jason Baehr states, it seems plausible that all necessary propositions are known a priori - and this position stems from Positivism - because "Sense experience can tell us only about the actual world and hence about what is the case; it can say nothing about what must or must not be the case".

In "Two Dogmas of Empiricism", Quine begins by making a distinction between two different classes of analytic statements.
  1. The first one is called logically true and has the form: No unmarried man is married A sentence with that form is true independent of the interpretation of "man" and "married", so long as the logical particles "no", "un-" and "is" have their ordinary English meaning.
  2. The statements in the second class have the form: No bachelor is married.A statement with this form can be turned into a statement with form (1) by changing synonyms with synonyms, in this case "bachelor" with "unmarried man". The notion of the second form of analyticity leans on the notion of synonymy, which Quine believes is in as much need of clarification as analyticity.
So for the sentence "All and only all bachelors are unmarried men" to be analytic, the terms 'bachelor' and 'unmarried man' should be synonymous (analyticity is explained by synonymity). And for two words to be cognitively synonymous, they must be interchangeable in every possible instance of these words, and the referents are necessarily identical. (synonymity is explaind by necessaity)

So, from the above example, it can be seen that in order for us to distinguish between analytic and synthetic we must appeal to synonymy; at the same time, we should also understand synonymy with interchangeability. However, such a condition to understand synonymy is not enough so we not only argue that the terms should be interchangeable, but necessarily so. And to explain this logical necessity we must appeal to analyticity once again, which means we have gotten full circle. Given any one term in the family-analyticity, synonymy, necessity-we could define the others. But since we can't explain any of the terms except by using the others, and since Quine thinks that all are equally in need of explanation, he concludes that the analytic/synthetic distinction, along with the necessary/contingent and the apriori/aposteriori distinctions, must be rejected.

But Quine's argument is effective only against positions that accept two of the positivists' fundamental theses:
Tl . All necessary (and all apriori ) truths are analytic.
T2 . Analyticity is needed to explain and legitimate necessity so a prioricity.
It is only when these two theses are accepted that Quine's argument holds. It is not a problem that the notion of necessity is presupposed by the notion of analyticity if necessity can be explained without analyticity. Both theses were accepted by most philosophers when Quine published Two Dogmas. Today however, both statements are to be antiquated.
  1. For T1, although some truths are both necessary and apriori, there are many examples of each that are not examples of the other. As for analyticity, opinions vary; the analytic truths are a subset of the truths that are both necessary and apriori.
  2. For T2, necessity and aprioricity are, respectively, metaphysical and epistemological notions that can stand on their own.

Kripke argued identity is not a relation that holds between names. It is a relation that holds between an object and itself. So when someone accurately claims that two names refer to the same object, the claim is necessarily true, even though it may be known a posteriori (can be known only through empirical investigation). For example, the proposition that water is H2O (if it is true). According to Kripke, this statement is necessarily true (since water and H2O are the same thing, they are identical in every possible world, and truths of identity are logically necessary) and a posteriori (since it is known only through empirical investigation). Also it is analytic because analysis of H20 says that it is water. Kripke's controversial analysis of naming as contingent and a priori would best fit into Kant's epistemological framework by calling it "analytic a posteriori".

Another example is the sentence, "the evening star" (Hesperus) is "the morning star" (Phosphorus). Here is an overview of the argument:
(P1) Hesperus is a proper name that refers to the evening star. Phosphorus is also a proper name and it refers to the morning star. They pick out the same thing in all possible worlds in which the thing exists.
(P2) Hesperus is Phosphorus. They are, in reality, two different names that refer to the same thing: Venus. This is necessarily true.
(P3) The fact that Hesperus is Phosphorus was discovered by empirical observation. So it is a posteriori knowledge.
(P4) Therefore, it is possible for knowledge obtained a posteriori to be necessary.
(P5) It is analytic because the predicate concept is contained in its subject concept.

With the example “Hesperus is Phosphorus”, Kripke seems to have provided a successful counter-example to the Kantian claims:
(a) P is a priori iff P is necessary.
(b) P is a posteriori iff P is contingent.

And also he provided a counter example to Quine's claim that the terms analyticity, synonymy, necessity are circularaly definable, so have to be rejected. Because now A prioricity, analyticity, and necessity have since been more clearly separated from each other. Although some truths are both necessary and apriori, there are many examples of each that are not examples of the other. Thus, the relationship between aprioricity, necessity, and analyticity is not easy to discern. the a priori/a posteriori distinction is epistemological, the analytic/synthetic distinction is linguistic, and the necessary/contingent distinction is metaphysical.

Hilary Putnam comments on the significance of Kripke’s counter-examples, ”Since Kant there has been a big split between philosophers who thought that all necessary truths were analytic and philosophers who thought that some necessary truths were synthetic a priori. But none of these philosophers thought that a (metaphysically) necessary truth could fail to be a priori”.


Noam Chomsky has taken this problem as a philosophical framework for the scientific inquiry into innatism. His linguistic theory attempts to explain in cognitive terms how one can develop knowledge of systems which are too rich and complex to be derived from the environment. One such example is human linguistic faculty. Human linguistic systems contain a systemic complexity which could not be empirically derived. The environment is too variable and indeterminate, according to Chomsky, to explain the extraordinary ability to learn complex concepts possessed by very young children. It follows that humans must be born with a universal innate grammar, which is determinate and has a highly organized directive component, and enables the language learner to ascertain and categorize language heard into a system. Noam Chomsky cites as evidence for this theory the apparent invariability of human languages at a fundamental level.

Parallels can then be drawn, on a purely speculative level, between the moral faculties and language, as has been done by sociobiologists such as E. O. Wilson and evolutionary psychologists such as Steven Pinker The relative consistency of fundamental notions of morality across cultures seems to produce convincing evidence for these theories. In psychology, notions of archetypes such as those developed by Carl Gustav Jung, suggest determinate identity perceptions.

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