Causation or Justification?

 

In philosophical writings about epistemology today there is a rather big to-do about internalist versus externalist accounts of knowledge.

I'll define the distinction here speaking very roughly. 

To an internalist, I know X to be the case if and only if (a) X is the case, (b) I believe X, and (c) I have a good reason, or warrant, or justification, to believe X.

To an externalist, on the other hand, I know X to be the case if and only if (a) X is the case, (b) I believe X, and (c) the reason why I believe X has an appropriate causal connection with X. 

The point of the labels is that justification (or whatever a particular theorist in this line may call it) is internal to my state of mind as the believer-of-X.  Causation may be entirely external to my state of mind. 

Direct sense perception provides the simplest example.  I form a belief that the leaves of this tree in front of me are green. It IS the case that they are green. The reason why I believe them to be green has a causal connection to their being green -- sunlight of the wavelength we call "green" just bounced off the leaf and entered my eyes. 

In this case, what modern folks who have passed some quite basic science courses mean by green is, roughly, surfaces off of which waves of just that length bounces. So one could hardly get a closer connection between (a) and (b). 

In such a case, the internalist might analyze the situation somewhat differently. He might say it is the case that the leaf is green, I believe that the leaf is green, and this belief is justified because I have consistently found my eyesight to be reliable and I have looked carefully at the leaf in good white light. the causal connection is at least somewhat less explicit here, the stuff internal to the believer's belief system is more explicit.  

What difference does it make? Why should I concern myself with internalism versus externalism?

Muddling up several possible answers here, I will point. Knowledge is often understood as a pyramid -- certain levels are more basic than others. Perhaps when we are young children we are already having experiences that are laying the bottom bricks, and later layers of brick have to be put on top of the layers already established, and if we live long enough we build toward a sky-high peak. Maybe the lucky get to shout "I understand it all now!" just before they die, as the final break, a peaked one, is put at the top. That kind of progressive optimistic view of knowledge, I imagine, is only possible given externalism. Because a literal pyramid always rests on something, such as the hardened sand where a fecund river valley meets a desert. The level hardened ground supports the pyramid, but is itself outside of the pyramid. Some external processes have to exist to get our reasonings started, however elaborate they may then turn out to be.