Stanford Encyclopedia : Perception
Wikipedia : Direct and Indirect Realism
On various philosophy forums I've participated on, there have been arguments between those who call themselves 'direct realists' and those who call themselves 'indirect realists'. The question is apparently about perception. Do we experience reality directly, or do we experience it indirectly?
When I was first initiated to the conversation, I immediately took the indirect side -- There is a ball, photons bounce off the ball, the frequency of those photons is changed by some properties of the ball, the photons hit my retina activating light-sensitive cells, those cells send signals to my brain communicating that they were activated, the signals make it to the visual cortex and...you know...some stuff happens, and I experience the sight of a ball.
So, my first thought in the conversation about Indirect vs Direct realism was that there was a lot of stuff in between the ball and my experience of it, so, it must be indirect.
But then I found that direct realists don't actually disagree about any part of that sequence of events I described above. For them as well, at least the few that have bothered to respond, photons bounce off a ball, interact with our retinas, send signals to the brain, etc. The physical process is apparently the same for both sides of the debate.
And when two sides vehemently disagree on something, and then when the question is broken down into easy, answerable questions you find that they actually agree on every relevant question, that tends to be a pretty good hint that it's a wrong question.
So, is this a wrong question? Is this just a debate about definitions? Is it a semantic argument, or is there a meaningful difference between Direct and Indirect Realism? In the paraphrased words of Eliezer, "Is there any way-the-world-could-be—any state of affairs—that corresponds to Direct Realism being true, or Indirect Realism being true?"
I believe that the answer depends on the perspective I adopt. This is the answer that makes sense from my current perspective.
If I model what I understand of your perspective within myself I would say that of course all my learning proceeds from some form of sensory experience, other claims are nonsensical.
With another model: The brain structures related to learning depend on more than just sensory experience, they also depend on the action of our DNA, gene networks, the limits of energy availability along with many other factors.
But why does the answer have to sensical from your perspective?
With another model: There is a process called MUP which is imparts knowledge in any form to the human mind. This is a process that by definition is any possible process not included by 'sensory experience' as defined by shiftedShapes. In other words MUP is any possible process, or perspective on a process that leads to learning beyond your claims about 'sensory experience'. Not being about to think of any examples of MUP does not disprove that MUP exists.
With another model: Blue hat.
And how did you learn about brains, dna, the concept of a process or blue hat?