Book Review : How to create a mind , Ray Kruzweil

The author Ray Kruzweil is known for his audacious prediction about near future. His prediction usually comes from his empirical understanding of how things work the way Greeks philosophers do.  He extrapolates his theories derived from 'thought experiments' to the maximum, and regress them until it fits empiricality. He has written many books that predicts future, and one of my favorite is 'singularity is near'. That book concludes that artificial reality is going to outsmart human at exponential rate. The prediction appears to be right in retrospect. Recent news from Google shows that NLP is already good enough to fool real person, and object recognition has out-perform humans in some competition. Some of those once considered the most difficult question a decade ago now looks basic to most engineers. The rate of improvement in AI indeed accelerates exponentially. This law is coined by Kruzweil as LOAR( LAW OF ACCELERATING RETURN)

He claims all information technology follows the same fashion, and Moore's Law incidentally being the most successful one. After all, our modern world is built on the computing power per unit cost, which essentially relies on miniaturization of transistors that improves at exponential rate.

The book How To Create a Mind tries to address a even more complicated question that humans have pondered since the start of history. How does mind work ? Or from engineering perspective,  how to create a mind ?

The book leads us through a series of thought experiments to deduce some basic properties of psychophysics. Some of the properties are already known by philosophers for a long time, but the author put them in light of artificial intelligence.

Chapter 1 :

Our mind that is able to retrospect the existence of itself is a unique ability of human being. Descartes's 'I think, therefore I am' can by self-evident, but it never lands on solid scientific ground. Consciousness, free will, and mind are just alternative words for soul in religious era. The essence of it is still elusive, and that's why having a theory of min is important. evidences of neuroscience are like words, but need a language -- a theory to put them into sentence. We need a unified model of our minds in order to understand how minds work.

However, is it achievable ?  The author believe it is achievable based on how scientists have successfully discovered Theory of Evolution and Theory of Relativity. They reminds us most people are limited by their ambition to see beyond their peers' believes.

Chapter 2:

The book is gigantic and worth reading times and again so here I just excerpt some quotation as footnotes of the chapter.
Q : Does the brain work the way how computers work ? 
No. We don't store every details of episodes of life in our brains. Our memories are stored in hierarchical manner. We only perceive and store those that are important to us. The selective filtering is achieved by a hierarchically organized receptive fields. Each layers reduce the dimensions (complexity) of features to push the neural networks to learn the representations is the most efficient way by attempting to minimize prediction errors. In retrospect, such hierarchical representation is effective because our world consists of objects that can be modularized into attributes of hierarchical abstractions. We recall our memories by reconstructing the input using the stored coding of the neuronal network through hierarchical layers(inverse forward method). This explains why our memories can be faulty in details while the emotional tags remain accurate.  Not only our explicit memories are stored in hierarchical patterns. The procedural routines of actions are stored in hierarchical patterns. Therefore we are able to generalize our motor controls by reusing the patterns. The same type of hierarchy also presents in our ability to recognize contexts and situations.   

 Our memories are stored in sequential patterns. We can't recall a series of number in reverse order easily. However,  they can be easily accessed in the order they are remembered. We are unable to directly reverse the sequence of a memory. This is manifested by the fact that associative learning of declarative memory (episodic and semantic) are encoded with LTP and LTD of inter-synaptic connections. The presynaptic terminal release neurotransmitters and post-synaptic dendrites have NT receptors to receive them. So the signaling pathways are directional.
We can recognize a pattern even if only part of it is perceived (seen, heard, felt), and even if it contains alterations.
Our recognition ability is apparently able to detect invariant features of a pattern -- characteristics that survive real-world variations.
Our conscious experience of our perceptions is actually changed by our interpretations. To solve a certain problem we need a certain set of policies to plan. However, the problem in real world is ambiguously defined. Therefore different interpretations occurs because each individual has varying policies and priors. We are constantly predicting the future and hypothesizing what we will experience. This expectation influences what we actually perceive.

Chapter 3 :
Neocortex is pattern recognition machine.