Krakatoa Day, 16th of Spring, 526 M.E. (Electra): From what I've seen in my own personal experience,  few teachings of the Buddha are more misunderstood than the 12-Fold Chain of Dependent Origination. 

I'm not going to get into the whole thing here. Suffice it to say, the teaching presents a dozen conceptual links, from old age and death down to ignorance, each dependent on the link below it for its existence. The confusion starts because many assume that the chain is somehow causal, and each link somehow creates the next link above. 

Based on how I just framed it, you probably suspect that I don't agree with that view. The link just below the last or highest link on the chain, old age and death, is birth. You can't have old age and death without first having birth, but it doesn't feel right to say that birth is the cause of old age and death (although it's sometimes said the life is a fatal condition).    

No, I see each link as a necessary substrate to the link above it. For example, you can't have fire without fuel, but fuel doesn't necessarily cause fire. Other phenomena, like ignition and oxygen, are also reuired substrates. Similarly, you can't have old age and death without birth, even though birth doesn't cause old age and death.

We can apply that substrate model to the first three, bottom links of the chain: ignorance, samskara, and consciousness. I use the Sanskrit samskara rather than the various English translations, because those various translations, which include intention, impulse, mental models, mental formations, and even memory, cause a lot of the confusion. Is ignorance the substrate for intention or is it the substrate for memory? Does consciousness require impulse or does it require mental formations (whatever those are) as a substate?

I think it can be readily shown that the Buddha meant mental models or mental formations, which are basically the same thing, as are Erich Fromm's "mental maps." Ignorance does create our mental models and they don't spontaneously arise out of ignorance, but we form them to help us understand what we don't know. As Michael Pollan puts it, we form them to help us predict the behaviors of the world around us in order to keep us safe. And one of those mental models is that the thinker is a separate thing from the rest of the universe - "I" am somewhere inside this skull, and outside of it are "others." It's "me" that's experiencing these senses, storing these memories, and forming these models.

"Consciousness," in this sense, means an awareness of one's self.  And it's our mental model of a separate self that's a necessary substrate for consciousness to appear. The awareness is consciousness - we're aware of our self - and while the mental model doesn't create the awareness, it creates the object of awareness. So without the model, there's nothing to be aware of and hence no consciousness, just like no fuel means no fire.

The rest of the 12-Fold Chain can be viewed the same way - to the next step, name and form, and so on all the way up to birth and old age and death. But right now, I've been thinking mostly about consciousness.