Epistemology and Machine Learning-01
Machines learning or learning machines (ML) have become one of the greatest obsessions of mankind and grew large in a short time period. Humans have put into thought how to create an intelligence synthetically or what we call Artificial Intelligence (AI) which could be similar to the natural intelligence of humans. However, ML and AI are now used practically everywhere and it has become very much familiar to people so some may not think where this learning new information & decision making capability of machines came from or whether they are even valid? Well, obviously one can say; we see empirical data or practical results and decide their accuracy at one point, but that is not how we would define their validity — in fact; “would this synthetic intelligence be valid & sound in general run” (or how they acquire knowledge and manipulate them is correct)? would be the question. An answer/explanation to this could be more or less philosophical which I am trying discuss in this article series. Such analysis could lead to understand not only the validity of AIs but also their limitations and potential too.
Human Intelligence
Arguably, humans are the most intelligent species in the animal kingdom and by nature they can perceive or comprehend the world around them more than other animals. However, this comprehension could be relative from person to person as well. Some intelligent people in the ancient world, pondered on the question, how could we be sure of our knowledge about the world and how we learn? Both great philosophers in the western and eastern world provided various answers, but here we will focus on the western part as its more related to our topic. Epistemology emerged as the way to answer this problem in western philosophy. Below text explanation was extracted from Britannica (https://www.britannica.com/topic/epistemology)
Nearly all human beings wish to comprehend the world they live in, and many of them construct theories of various kinds to help them make sense of it. Because many aspects of the world defy easy explanation, however, most people are likely to cease their efforts at some point and to content themselves with whatever degree of understanding they have managed to achieve…
…Unlike most people, philosophers are captivated — some would say obsessed — by the idea of understanding the world in the most general terms possible. Accordingly, they attempt to construct theories that are synoptic, descriptively accurate, explanatorily powerful, and in all other respects rationally defensible. In doing so, they carry the process of inquiry further than other people tend to do, and this is what is meant by saying that they develop a philosophy about such matters…
Simply, Epistemology is about how humans extract and attain knowledge. This also includes notions (a concept about something/an abstract idea) of things such as knowledge, information, truth and reasoning, which is (simply) how we could define them.
You are a peasant from an ancient lost tribe, you wake up in the morning for the daily routine but you find the guards from the head priest’s palace at your doorstep. Well, you are the chosen one for today’s human sacrifice- what an honor!!! Head priest is well knowledgeable on how to choose the sacrifice and as well as what would happen if the god is not pleased. You are not sure how the priest knew all these but….who are you to decide? After all, you are only a peasant.
Well I’m not sure whether this example would be the best, but I think it shows how important it is to validate our knowledge and the perceived world of humans. Now, we don’t want to mess with divine powers, do we?
I would not try to explain the philosophical terms in deep but only relevant to our discussion. So, Coming back to our topic, Aristotle(384 BC — 322 BC) and Plato (428 BC — 348 BC) who are regarded as probably the greatest figures in western philosophy were pioneers in developing ideas related to epistemology. The main phases of epistemology could be said; attaining the true knowledge and its truth-preserving manipulation. However, the second one is the aspect that mostly had the attention of the ancient philosophers, which can also be referred as logic (or Deductive logic). The Greek and Roman philosophers are said to be the ones who systematized the method of deductive logic.
A fact that could be the reason for the lack of development of the first phase is the idea of the inaccessibility to the truth (eg:- “Theory of Forms” and “Allegory of the Cave” by Plato). Another reason could be the belief of that true knowledge could only be attained by some initial inspiration, made possible by a higher power (or God).
Allegory of the Cave
This allegory (a work of literature/art containing a hidden meaning) comes in Plato’s Republic. The story goes like this,
Suppose there are some prisoners in a cave, who are chained against a wall, so that they cannot move or look around but can only see the wall and they have been living like that their whole life. Behind them, is a fire and in front of the fire there are people or puppeteers and only the shadows of their objects or puppets are visible to the prisoners (prisoners do not know there are puppeteers/people) . What would be the reality of the prisoners?
This has other parts to it also, but the main idea is that the prisoners are in a delusion and that they do not know the actual reality. This goes by the Plato’s “Theory of Forms” as well. Which is, that the physical world is not as real or true as timeless, absolute, unchangeable ideas (Wikipedia). What Plato tries to state is that, humans cannot know the exact truth or reality from their normal perceptions of the physical world or everyday experiences in the physical world. These ideas had political motives behind them too. However, they shaped the initial development of epistemology.
Deductive logic
Logic lies at the heart of modern sciences. It defines a method on how to construct a proper reasoning which means you can transform true statements to other true statements. The general structure of a logical reasoning or argument is, you have some statements which are either true or false(premises). From them, you try to reach another statement (conclusion) through proper reasoning. These statements can collectively be called propositions. Below is a simple argument. There are many forms of logical arguments which will not be our main concern here.
Every mammal has four legs(premise)
Cat is a mammal(premise)
— — — — — — — —
Cat has four legs (conclusion) — — — — — — — → valid, not sound
Every mammal has four legs(premise)
Whale is a mammal(premise)
— — — — — — — —
Whale has four legs (conclusion) — — — — — — — → valid, not sound
Well, logical reasoning can be valid (like above) but not sound. Yes, exactly! Logic concerns about the pattern or the mechanism of argument but not the content (“not factual claim but inferential claim”), i.e.- the quality of reasoning. So, for an argument to be valid (deductive argument), it only has to be well-formed, but to be both valid and sound, the premises should also be true. (Having true premises and false conclusion will be invalid)
Next, I will try to write more about epistemology, reasoning, empirical sciences etc. reaching to the context of ML. Please add any feedback you have. After all, I’m not an expert in philosophy too. Thank you for reading!
I was inspired by the mainly text, “Chapter 02, Handbook-Statistical foundations of machine learning, Second edition, Gianluca Bontempi, Machine Learning Group, Computer Science Department, ULB, Universite Libre de Bruxelles, Belgium”
