A jcf.org forum member asked 'What is thought?' This was my response.
Ah, an interesting question, for sure.
I like to ask, 'how much does a memory weigh?' Since the brain is matter, and the matter has weight, and the brain is capable of massive amounts of information storage, then the memories must be part of the weight of the brain, ergo, what does a memory weigh?
And, while the brain seems to be of a fixed size, our consciousness is rather infinite. So we have an interesting phenomenon of a physical universe that stretches out forever and an internal universe inside our head, of a consciousness that can stretch forever, too.
And, we are aware of our own consciousness, which is a lot different than time and space. We cannot create time or space, but we can create our own consciousness.
Everything is a seed of a seed. Life begets life. This is true even in the 'mundane' physical universe. Oceans become clouds, clouds become rain, the rain becomes rivers, the rivers become oceans. The same thing occurs with galaxies, etc. We are conscious (or can be) of a gigantic ballet swirling all around us. We are part of the ballet. (It really isn't a heroic journey at all, but more like being a passenger on a bus.)
From ashes to ashes. From dust to dust. How can dust hold consciousness? Logically, we can only return to a greater mystery, which is the word God. God can be thought of as the first edge of mystery (not the last.) We can figure out enough to get to the edge, but not beyond it.
So what is thought? Is the purpose of thought to bring us to the edge, like salmon running up the rapids? Or, was the purpose of thought so we could enjoy the effort to swim up the rapids? Or, was the purpose of thought the spawning that takes place at the end of the rapids? Yet, all of the universe is experiencing this same paradigm, with or without consciousness, living mater or not. Thought is only necessary to make us aware of it, but not to direct it.
Perhaps I am answering 'why thought?' rather than 'what is thought?' Certainly, if thoughts have a physical make-up, then they should be measurable by weight. But even weight is just an illusion. Gravity is created by the density of matter, but none of the matter has any weight. In many areas, and this is another, the sum seems to be greater than the parts. This makes no mathematical sense, like feeding thousands with a single loaf of bread and a couple of fish. Why would a billion weightless atoms give the Earth density and weight? Logically it should still be weightless, yet the Earth is held in place by the Sun. So how does a weightless Sun hold a weightless Earth in a weightless universe, yet we can feel its heat on our skin?
We can feel, taste, hear, see and smell the physical universe, yet our brain processes it completely differently. Thoughts govern the five senses, and the five senses govern our thoughts. 'What is thought?' could just as easily be 'Is thought real?' Is the physical world real? Are we at the edge of God's reality or just trying to find balance between our senses and out thoughts? Do we defer to reason or mystery?
We are locked out of the room. All we can do is peer through the keyhole. What we can see is a very narrow view.. If we knock, the door will open, we will be invited in, and we will know all there is of good and evil. Well, assuming we even care about such things anymore. Certainly if we can pass from a state of non-thought to a state post-thought, then there is more to ourselves to understand than just the physical, but I don't think we will be able to weigh a memory or a thought anytime soon. We are stuck at the edge of mystery.
imo, it is far more reasonable to declare there is a mystery, than it is reasonable to declare there is none. We awaken on a bus, with no remembrance of boarding, no ticket, destination unknown.