Grinding It Out!

Written by Chirag on Sunday, July 19, 2015 at 6:30pm

 I grinded through my weekly schedule.  One coincidental fact to add was that the Recursion book I am reading quoted Douglas Hofstadter’s GEB book.  This gives me further confidence that recursion might be a useful tool for building intelligent machines.

Here is a basic thought process on when to use recursion. A problem must have three distinct properties.  This is directly quoted from Thinking Recursively by Eric S. Roberts

* It must be possible to decompose the original problem into simpler instances of the same problem.

* Once each of these simpler subproblems has been solved, it must be possible to combine these solutions to produce a solution to the original problem

* As the large problem is broken down into successively less complex ones, those sub problems must eventually become so simple that they can be solved without further subdivision.

At the end of the first chapter, there were three problems to solve.  The last (and the difficult one) asked to find a light weight (counterfeit) coin among 16 coins. If you had a balance which you can use to compare two coins, how many trials would it take to find counterfeit coin among the 16 coins.  The standard answer is four trials but you can do better than that. The answer here is three.   I have uploaded a recursive solution (Recursion1\divideandconquer.py) on my github account.

I also ordered Rajesh Rao’s book Bayesian Brain. This will be on the next reading schedule. I also thought more about reaching out to Neuroscience PhD students. I really want to understand what I can gain out of attending a Neuroscience PhD program. So I have reached out to NJIT, UC San Diego and UT Austin Neuroscience programs.

Strange Loops

Written by Chirag on Sunday, July 12, 2015 at about 2:35pm

Over the past week, I have been more aggressive in trying to keep up with my schedule.   I have added one more book to my weekly reading list and have defined a key question that needs to be answered by science.

1) I have added Thinking Recursively by Eric S. Roberts.

2) The key question is why does our brain think it is alive?  To me it is endlessly fascinating that you can put together bunch of chemicals (as in what’s in our brain) and if put together exactly right, you create a system that thinks it is alive? How does this happen?  To me only person, who has even tried to ask this question and come up with a solution is Douglas Hofstadter in his book GEB. More on this a bit later!

Recursions and Strange Loops

Recursion: Separately, my view is that Strange Loops (Douglas Hofstadter’s Theory) and Recursion are quite related.   Also, as I read more about HTM, I don’t think the Brain uses Bayes’ Theorem directly.  It is coincidental as in the Brain is a memory system, so it is constantly using priors to make future predictions.  So it gives us a feeling that it is using Bayesian Inference to come up with a most likely outcome.

It’s worth emphasizing that Vicarious (AI company) algorithms are defined as Recursive Cortical Networks (RCNs). As per wikipedia, RCN is a visual perception system that interprets the contents of photographs and videos in a manner similar to humans. The system is powered by a balanced approach that takes sensory data, mathematics, and biological plausibility into consideration. On October 22, 2013, beating CAPTCHA, Vicarious announced its AI was reliably able to solve modern CAPTCHAs, with character recognition rates of 90% or better.

Also, I think Recursion by itself is a pretty cool tool to have in your arsenal as it is a super awesome problem solving technique.  I have coded my first recursion example in Python. Yes, am getting little more comfortable with Python and have pushed it out on my Github account here: https://github.com/g402chi

Strange Loops:As I am reading GEB by Douglas Hofstadter and his theory of Strange Loops. Example of Strange Loops are Catch-22s or Which came first the Chicken or the Egg. I like to use examples first because that is usually the easiest way to get a point across.

As per wikipedia:”A strange loop arises when, by moving only upwards or downwards through a hierarchical system, one finds oneself back to where one started.

Strange loops may involve self-reference and paradox. The concept of a strange loop was proposed and extensively discussed by Douglas Hofstadter in Gödel, Escher, Bach, and is further elaborated in Hofstadter’s book I Am a Strange Loop, published in 2007.

A tangled hierarchy is a hierarchical consciousness system in which a strange loop appears. In short, a strange loop is a paradoxical level-crossing feedback loop”

I realize Douglas Hofstadter, in his book GEB, is absolutely trying to answer the right question.  As in how does the brain of any given animal think it is alive.  This is the most key, tremendously important, question that modern science should be trying to answer.  My conjecture is that we can not build truly intelligent machines until we answer this question. My guess on the future is that if the nature is able to build this brain that thinks it is alive, it must be possible to do it.  We need to figure this out. I am not even talking about a human brain, take a C. Elegan brain, ant brain.  However small you would like it to be. All these insects, they are self aware and are acting on their behalf only.

As per Douglas Hofstadter,

“the psychological self arises out of a similar kind of paradox. We are not born with an ‘I’ – the ego emerges only gradually as experience shapes our dense web of active symbols into a tapestry rich and complex enough to begin twisting back upon itself. According to this view the psychological ‘I’ is a narrative fiction, something created only from intake of symbolic data and its own ability to create stories about itself from that data. The consequence is that a perspective (a mind) is a culmination of a unique pattern of symbolic activity in our nervous systems, which suggests that the pattern of symbolic activity that makes identity, that constitutes subjectivity, can be replicated within the brains of others, and perhaps even in artificial brains.