A Causal Theory of Knowledge I

 

Recently in this blog I spoke of the death of Prof. Gettier, and of post-Gettier problems in epistemology. Prompted by a response to that post, I will in today's and tomorrow's entry go further on this subject. 

My own views have changed in quite recent months, in large part through my discovery of Alvin Goldman's essay, "A Causal Theory of Knowing" from 1967, only four years after Gettier's famous essay. 

Goldman looked at only a piece of the puzzle, the knowledge of the perceived world. He set aside the question of what it means to know, for example, that 45 + 303 = 348. He was concerned with knowing something like "this leaf is green." 

If knowledge is "justified true belief," then I know this leaf is green if and only if (a) the leaf is in fact green, (b) I believe that it is green, and (c) I can see the leaf, and (say) I have recently had my eyes checked so I am confident in the health of my vision. Note that the justification element is interior to my belief system. Things like my memory of my recent visit to the ophthalmologist, and my confidence in HIS qualification, may come in here. 

But Gettier had complicated that account, and Goldman sees the complexity as arising from the internal nature of the idea of justification. CAUSATION, on the other hand, is external. I know that this leaf is green if and only if (a') the leaf is in fact green, (b') I believe that it is green, and (c') facts about the leaf stand in an appropriate causal relationship with the development of my belief. 

A broad definition of when the causal relationship is appropriate would, of course, be tricky. But let us stick to this example. This is New England and it is not yet October. The leaves have lots of chlorophyll in them and this means that they absorb light at the two ends of the visible spectrum and reflect back light in the center. That means that my eye takes in light of that wave length. We don't need to concern ourselves with our internal beliefs and ophthalmologists to judge that the way the world is has caused me to believe something truly about the way the world is. I have perceptual knowledge.  

What can I say about 45 + 303? We might carry Goldman's idea through in a straightforward way if we are Platonists, or rather Pythagoreans about the nature of number. But I am not and I doubt many of my readers are, either. More on this tomorrow.