Empiricist arguments against innatism

What is the lack of universal consent arg claiming?

Those who support innatism often claim humans must have innate ideas/knowledge since some ideas/knowledge is found universally. Yet, it would be improbable that these universal ideas/knowledge come from a shared experience. Therefore, any universal ideas/knowledge must instead be innate.
Against this innatist line of argument, Locke argues there is no universal consent. There are no ideas/knowledge that all people across time and location share. Locke argues that children and "idiots" do not know logical principles, or God

What is the lack of universal consent arg + transparency of ideas?

R1: Any innate idea, x, if it exists, would be universally held.
R2: Children and idiots do not have the idea of x.
R3: The notion of a person having an innate idea, x, and not being aware of it does not make sense. (The transparency of ideas.)
IC: So, x is not universally held.
C: Therefore, x is not innate.

What is Leibniz's defence against the transparency of ideas and lack of universal consent arg?

-Some philosophers argue that all people share certain ideas/knowledge, yet they may be unaware. Perhaps particular ideas/knowledge are present in the mind, but the mind cannot yet express these ideas/knowledge in language. Or, conceivably, certain ideas/knowledge are in the mind potentially, as ideas/knowledge the mind is predisposed to.

How might the response that ideas/knowledge are present in the mind, but the mind cannot yet express these ideas/knowledge in language be replied to?

Wittgenstein has argued that it is not possible to have wordless thoughts. All thoughts, if they are to be meaningful, must be in some form of language and all language must be public (An entirely private language (one that has no shared rules) is indistinguishable from meaningless noise.

How might the response that certain ideas/knowledge are predisposed in the mind be replied to?

Locke will insist that an idea/knowledge can only be in the mind if the subject is aware of it, at least at some point, which coincides with the idea/knowledge's entry into the mind. (Memories can be in the mind, while the subject is unaware of them, but memories were formed at some point of awareness.) An idea/knowledge is a thought, and thoughts only exist when thought. There is no such thing as an unthought thought in the mind.

How could this be responded to?

Maybe innate ideas/knowledge are potential predispositions of the mind - the mind is inclinded to form them given the right stimuluous. The human mind has evolved in such away as to develop certain innate ideas/knowledge in this sense.

How does the work of Carruthers support this?

Carruthers provides empirical evidence for this argument:
- developments in cognitive capacities are genetically determined- infants cannot see further than 12 inches when first born. Within 8 weeks, they can see much further.
- The same could be true for certain types of knowledge. At a certain genetically determined point in development, children begin to think in a particular way for the first time, but that way of thinking has not been learned from experience. For example, around 3-4 months, babies quickly shift from thinking of objects as existing only while they experience them to thinking of objects as something that can exist outside their experience.

Why does this not completely solve the problem?

The innate ideas would be contingent. What about necessary truths? Perhaps we have to say they are analytic conceptual truths, which we gain by language acquisition. We could then argue that perhaps humans have evolved to develop language within a certain range. If these mathematical and geometric truths were conceptual and analytic truths gained by language acquisition, then it seems they would be contingent, which does appear odd. It seems odd that they should just be the product of the contingent evolution of a human brain and not necessarily true in all possible worlds.

Why does universal consent (or its lack) prove nothing?

Universal consent does not prove that the idea in question is innate. Whilst it is improbable that, there should be some experience all go through, it is not impossible. Perhaps there could be some shared experience which explains a supposed universal idea, which would mean we did not have to maintain that this same idea was innate. For example, consider the idea of God, understood as a supremely perfect being. Rank, the argued that a desire for mystical union with the cosmos is the product of birth trauma. All would share the experience of birth trauma and so the universality of a concept of God is explained by a universal experience. Hence universal consent proves nothing innate.

Why is it not clear that universality is a necessary condition for innatism?

Perhaps, using Plato, only some remember their previous life in the land of the Forms. Or, maybe using Descartes, God only chooses to stamp a trademark of Himself on some people. Alternatively, using Carruthers we might say, only some individuals have the genetic encoding to develop innate knowledge and ideas.