The statement “you know that you are reading this book,” has to be based on the premise that we can actually know anything as all. That, in turn, leads to questioning where we get our knowledge from in the first place.
Furthermore, even if one was to find an answer, could it be proven sufficiently beyond doubt, to be verified as a true answer? These are two of the points put forward by René Descartes.
Many Philosophers, from different viewpoints, have presented ideas which they used to answer similar questions; and by virtue of this, can also hope to answer this question.
René Descartes came to the conclusion that the only thing that we can definitely be certain of is the fact that we, or rather I, exist. That is, because Descartes came to believe that in order to think, something must have to exist consciously, in the first place. As a result, as he thinks he must exist, so he can be certain that he knows that he exists. Hence his phrase, ‘I think, therefore I am.’
However, this brings us brings us back to the first point, “you know that you are reading this book”. The problem, it could be argued with Descartes’ answer, that he can be certain of his existence, only, because he thinks; is that it cannot be applied to outside objects or rather the external world. In other words, because you cannot tell if a person, is thinking, and not just talking, you cannot know if they exist. The same goes for all other objects.
The evidence for the existence of the external world falls far short of what is needed, if Descartes’ ‘I think, therefore I am,’ is to be taken as the only premise for true existence.
This concept is furthered by Descartes’ idea of the malicious Demon. Although we, or I, must exist (we know this from ‘I think therefore I am), we do not according to Descartes, really know that the world around us exists. It may just be the work of a malicious demon. Or, it may be the modern day equivalent. We may just be Brains in vats. We just don’t know. This is the view of the Sceptic.
Even though it does, at first, look as though the sceptic is the only person who can be right, G. E. Moore, disagreed. He says that the Sceptic must be wrong. There are, he says. Certain things about himself that he knows are true. ‘There exists at present a certain human body, which is my body…Among the things which have…formed part of its environment…there have…been large numbers of other living human bodies.’
Moore goes on to say that each person knows about themselves, what he knows about himself. Furthermore, we each know these things to be true about everybody.
Moore then takes the argument another stage and further renounces the Sceptics. First, he makes the point that if Sceptics are actually Sceptics and doubt everything, even that they exist, who are they writing the books for? Then he takes this argument once more against the Sceptics, that we cannot know everything by, in his mind, proving the existence of his hands. First, Moore holds up one hand and says ‘Here is one hand,’ then he holds up another and says ‘Here is another’. This is where his argument comes from. He knows that his two statements are true. Moore goes on to conclude+ that ‘Two human hands exist at this moment’. From this, Moore says that he knows two material objects exist. As a result, if we followed Moore, we can also know the book, which apparently I am reading, is real.
Ludwig Wittgenstein generally agreed with Moore. However, he believed that Moore’s argument lacked one main thing, context. Wittgenstein argued that things only make sense in certain contexts. One example of this would be if a person had been in an accident. He wakes up, lying in hospital with his hands bandaged. If he were to say to himself ‘I know I have two hands,’ in relief, this would – according to Wittgenstein – make sense. This is, because there was real doubt, whether or not people had hands. However, according to Wittgenstein, it would not make sense to just say ‘I have two hands’.
According to Wittgenstein, as Moore had no reason to doubt whether he had hands, his statement that he had hands had not context and made no sense. He believes that a Philosophical context is not one in which to doubt the existence of hands. Wittgenstein said that the fact that human beings have hands is just one of a number of empirical facts which we do not learn as children, but which we simply accept as part of our view of the World as a whole. If we were to doubt such things as this, we soon have to start to doubt everything.
In the view of Wittgenstein, the existence of the external world is a fundamental condition of existence, as such, to doubt its existence would make no sense. So, we must, according to Wittgenstein, believe in its existence and as there is no alternative, know that it exists; and by that same virtue, know that the book being read exists.
Putnam took the idea of context affecting whether things make sense, or are true, to the environment in which something is in. Putnam’s ideas can be best explained through the following – edited version- of his thought experiment.
Suppose there are two Planets, one called Earth, the other called Twearth. On both planets there is stuff that looks, tastes, smells, feels and is, for all intents and purposes – water. However, only one of them is actually water, H20 as we know it, the other is Twater, XYZ. On Earth there is water and on Twearth Twater. However, on Twearth, Twater is called Water, as water is called water on Earth. This means that when Earthiens and Twearthies use the word water, they mean different things. This is, because their physical environments are different.
What Putnam means in his thought experiment, is that what a person means when saying something, cannot be understood by what they think they are saying. The environment that they are in alters what they mean. Putnam summarises this by saying ‘meanings aren’t in the head.’ So the book that I think I am reading, may not be a book, it may be something else.
Like Wittgenstein and Moore before him, Putnam used his ideas as an argument against Scepticism. To show how they can be used, Putnam used the Sceptics analogy of the Brain-in-a-Vat. His argument goes basically as follows. If you were a Brain in a Vat and thought about reading a book, you could not be thinking about reading a book. Being a Brain in a Vat, you wouldn’t know what a book is. There isn’t any book to think about. All that you know as a book is what a mad-scientist type person, is putting into you. You would have had to come into contact with a book, outside of the confines of this analogy. As meaning ‘aren’t in the head’ a person who had actually read a book would be thinking about something different to the Brain-in-a-Vat, who had not experienced an actual book.
Putnam then goes on to use the Brain-in-a-Vat to prove that there is no Brain-in-a-Vat. If a Brain-in-a-Vat made a statement saying ‘I am a Brain in a Vat,’ the statement becomes false. It is not a Brain-in-a-Vat as it and we suppose – it does not know what one is. So as the statement ‘I am a Brain-in-a-Vat’ is false, Putnam argues that there is no Brain-in-a-Vat. He described this sort of idea as a ‘reducio ad absurdum’ or ‘reduced to absurdity’. Questions involving such levels of Scepticism cannot be supported sufficiently and can be proved – Putnam feels- to be absurd.
With regards to the question about knowing about reading, Putnam would probably argue that what we mean is a Book, is not a Book. However, by developing this idea, as was done with the Brain-in-a-Vat, we negate it. So, we can know that we are reading a Book.
After examining the responses and ideas of Moore, Wittgenstein and Putnam, there can be little doubt that the statement is true. I know that I am reading a book, as there is no other possibility. Or rather, there is no other possibility that stands up to scrutiny. Any sort of Scepticism, could be overcome by the arguments of Wittgenstein and Putnam, leaving Moore’s simple idea, that we simply know that some things are, what they are, to leave me certain that the statement is correct.