Two Examples of Downward Causation

 This spring I proudly announced on this blog that I believe I have achieved reflexive equilibrium on the issue of the relationship of the mind and the body.

I am, I said, "an emergentist, and specifically one who embraces downward causation and a planetary mereology."

I also tried at that time in the main text and in a brief exchange with Henry to explain what emergence means and why my mereology (my sense of parts and wholes) is planetary. For now I will just say that if we do discover life on other planets, I will think it perfectly moral to declare oneself an Earth Chauvinist.

Today I would like to speak a bit about downward causation.   

If we think of reality as layered, so that matter was a layer added on to space and life a layer added on to matter, then one might well ask: are events in the upper layers explained fully by events in the lower? And are events in the lower explained fully by themselves? Can we explain all of biology as chemistry, and all of chemistry without regard to biology? If so, then we might say all explanation points upward. But I don't think that is so. 

What are some examples of downward causation? 

Consider this attempted answer: a pet turtle dies and the boy who had cared for it cries. In this simple assertion we can stipulate that there is a biological event (the boy's perception of the death of the turtle) followed by a mental event (sadness) followed by a physical event (the physical manifestations of that sadness such as the flow of tears out of eye ducts). 

But we have a problem here: the James-Lange theory of emotion. According to that now venerable theory, our boy is sad because he is crying, not the other way around. 

So let us vary it a bit. The boy, offered a chance of another turtle pet, turns it down. This turning-down manifests itself in a vigorous shaking of the head. We might call THAT a consequence of his sadness, considered as a mental fact. We say things like "he doesn't want to love and lose again." I think in this case common speech has it right. We do act for reasons, which develop as we live, and in such a case mental facts are the correct explanation of physical facts. 

Another distinct example would be a situation in which a biological fact proves the correct explanation for a physical fact. A dog eats a piece of kibble.  as illustrated above. Let us just focus on the moment when the dog puts the piece of kibble in his teeth and his neck straightens out so he is looking straight forward from the axis of his body. That piece of kibble has moved upward from the bowl. If the dog didn't exist, and the kibble made the same movement, it would be a magical leap upward, "for no reason." 

Yet it wasn't magic. There is a reason. We cannot understand that reason except through understanding that there are carbon-based creatures in the world with their own non-mechanistic imperatives, including a survival instinct that leads them to put kibble in their mouths. 

So let us return to the italicized formula above. I am "an emergentist, and specifically one who embraces downward causation and a planetary mereology."

I hold, then, that life emerged from non-living matter and mind from unmindful life. The emergence itself is upward causation. Those events took place in the depths of geological time. Because they have taken place, some of the particles of that kibble will in due course become part of the body of the dog. The upward causation is genuine, as is the causation in the other direction. The will-to-live as expressed in the dog causes motions of kibble particles. At the next level up, sadness (a mental fact) causes changes in the behavior of some of these organic creatures. 

I don't claim for these propositions the status of scientific theorems. I assert them as integral to a valuable vitalist philosophy, one that is not fully underwritten by, but is also not contradicted by, the relevant sciences.