Now this particular proposition came to be developed further, particularly through Socrates and Plato and it opened up another dimension of rationality, based upon this idea of Parmenides but there was another dimension and if you want to examine the structure of the argument, you will find from a simple example that Socrates himself says: If two things are similar, you must ask why they are similar, it is the structure of the argument. If two things are similar, if two cats are similar to each other there must be a reason why they are similar? And the search for the explanation of the similars offers the purpose of rationality. So this was also developed that is to say there must be something which remains the same in two things, which look similar and that which is the same thing between two similar must be real. And you must refer to their reality to be able to understand all that is there in the world. This is the structure of the argument. It is on that basis that if you look more deeply you will find in Plato his theory of form, or the theory of ideas, or the theory of universals, he came to the conclusion that the ultimate Reality must be permanent as in Parmenides, it must be universal and it must be the cause of all things which are moving in the world. We must remember that in Parmenides there is no clue to understand the movement because a movement does not exist, cannot exist, it cannot be understood, does not exist. Plato however more synthetic in his approach, he had to deal with the problem of the movement and he tried to accommodate the movement within the grasp of the permanent which he described as that which remains the same, but which is also now described as the universal. And his whole concept of the Good, which he regarded to be the Reality, that Good is universal and it is that in which all things in the world can be subsumed, all the multiplicity, all things which look similar, there are types and types of people, types and types of things, all this can be generalised ultimately into the highest universals. And the highest universals are three – Truth, Beauty and Goodness and these three can further be subsumed under the highest Good and that highest Good is the ultimate Reality.
Now you can see how the rationality took a farther step in Plato. Now this farther step however had many deficiencies and very importantly Plato in his dialogue called Parmenides is very significant, he examines his own theory critically through the mouth of Parmenides and that is because the question of movement which Plato thought has got to be subsumed under the idea of the Good, surely he was not very sure whether it was really subsumed or to be extinct. How to explain what may be called in the Indian terms the Being and the Becoming and how the two can be combined together, reconciled together, that was the problem which Plato could not resolve. And in his dialogue Parmenides the deficiencies of his theory are themselves criticised by Plato himself. He was aware of the deficiencies. It is on that deficiency which was there in Plato that Aristotle went one step farther and I will not go into Aristotle because it is another track altogether but there is a slight deviation in the movement of rationality when we go from Plato to Aristotle. He also realised that it was not possible to explain the synthesis of the Being and the Becoming. He tried in his many ways and the whole philosophy of Aristotle is nothing but his attempt to reconcile the Being and the Becoming. Ultimately however his fundamental contribution was to analyse the becoming. And that is now the new shift which they take in the Western thought. The idea of the Being was put to some extent put aside and the greater emphasis was laid upon the phenomena of the Becoming. And in his circle we must know that Aristotle himself was the father of many sciences and the sciences are the study of the natural phenomena and it is the science of Becoming. But following the Parmenidesian tradition, Socratic tradition, Platonic tradition, we see in Aristotle explanation of the Becoming strenuously tied up to the concept of the Being, not reconciled but strenuously tied up with the idea of the Being. And what is the form that it takes? And in that context we must know what exactly Aristotle understood by the word rationality.
In fact we all know that it is Aristotle who gave us the first fundamental of logic, which remained alive for two thousand years until what we call the modern logic, symbolic logic came to be developed. But the theory of logic that he gave remained supreme throughout the whole history of Western thought right up to the present day. Even now Aristotlian logic is supposed to have been subsumed under the modern logic, it is not denied but it is supposed to be subsumed. But what is important for all purposes is to realise that his enunciation of logic was a discovery of the inner structure of rational thought and he pointed out that any human being could speak rationally, if guided by their inner structure and what is that inner structure? And for him the Platonic ideal, he said that the structure consists of relating the universal with the particular. Our experience of the world is the experience of particulars. And these particulars can be rationally understood only when you discover a universal. And the structure of human reason is such that the particulars can be subsumed under the universal. He went one step farther in this discovery of the structure, that if this structure is to be remembered that in order that our thought is rational and therefore valid there must be a strict adherence to what he called the concept of identity. And this is a very important concept of rationalists. A proposition is undoubtedly true when the subject and the predicate are sustained – a cat is a cat. Nobody can doubt it, or a tall cat is tall, nobody can doubt it. It is because of identity. And identity idea is arrived at from the idea of permanent and the idea of universality, when universality and permanence, when these two ideas are put together then you get the real idea of identity. You can explain everything in the world rationally only if you ultimately refuse this state in terms of universality and identity. It is significant therefore that the three laws of thought which came to be formulated and leave actually are the mark of rationality are the law of identity, the law of contradiction, and the law of extruded middle. Now these three laws actually are nothing but restatement that a proposition is valid only if the predicate somehow can be shown to be identical with the subject. You can be sure of the proposition, any knowledge can be sure of, can be rationally valid only if you can ultimately reduce whatever you want to say in terms of identity. There should be no contradictions, if there are contradictions it is invalid and if you say that it is partly here, partly not there will also not be allowed, either it is yes or no, that is extruded middle. When there are two propositions and they are in conflict with each other, only one can be true the other must be false, if the two propositions are contradictory of each other. It is also true of the later people when he came to define inductive logic he made a very important discovery. That whenever we look at particulars in this world, there is a surprising phenomenon and that phenomenon is that our mind gives a leap, our rationality makes a leap and what is the leap, going from the particular to the universal. It is again written to Platonism. Ultimate Reality is the same, permanent, it is universal and therefore thought of, when you see particulars, particulars cannot be understood properly, rationally, unless you make a leap with universality and therefore inductive logic is nothing but rules and regulations which are to be observed in order to move from particulars to universals. So he came to see that all rational processes in the world are either deductive or inductive. If it deductive, it is relating universal with the particular. If it is inductive it is relating the particular with the universal. This became the hallmark of rationality. It is nothing but the discovery of the universal and the permanent in the flux of the plurality and the multiplicity that is there is in the world. We must remember that this data lately was not able as yet reconciled the particulars and the universals, it was not able to reconcile the becoming and the being.
Now this failure of the Western rationality has remained throughout the history. Now I omit at present the consideration of rationality as it came to be in the Middle Ages after Aristotle. And I come straight to Descartes because he is a rationalist of the modern times and in Descartes there is a restatement of Platonism and also the logic of Aristotle, there is no departure at all from the principles of universality and permanence and so on accept that there was a new attempt on the part of Descartes and he underlined a new analysis if the human rationality, it is the fresh analysis. And this analysis started with the affirmation of doubt. Descartes is famous for the Cartesian doubt. In order to be rational you must come to universal permanent but if you simply asserted, it is not rational, you must arrive at it, you must be sure about it, you must have self verification of this principle and how do you do it, therefore he starts a process of doubting and he said you can doubt the whole world, you can doubt your mind, everything at all, everything can be doubted until he came to the phenomenon ‘I think”. It is the one proposition which you cannot doubt because the very doubt implies itself by thinking. So the instrument by which you doubt is itself an instrument which affirms what you are trying to doubt. And therefore ‘I think’, he said is incorrigible. It is a very important term incorrigible, intellectually it cannot be corrected. I think it is an incorrigible statement. Of course on the basis of this ‘Cogito ergo sum’ he developed the proof of the existence of God and also the existence of the self, of the soul. And it is very remarkable that his proof of the existence of God, if you examine properly it is nothing but the restatement of those two sentences of Parmenides. I will not dwell upon it, I leave it for further, at any time if you want to discuss it, we can discuss it. Very important, the argument that Descartes gave of the existence of God and proved the existence of God is nothing but proof of Parmenides of the problem of being. This argument has been famous as the ontological argument which was restated by Spinoza. In fact Spinoza is a kind of a climax of Platonism, of the theory of Aristotle, of Descartes and brings the whole rationalism to a grand finale you might say. In his ethics the way in which he has tried to demonstrate philosophy – geometrically, so as to show thinking can be absolutely logical and concluded in which no doubt remains at all. In which he once again reduces the whole universe in one permanent principle of the Absolute, which is universal and which transcends all limitations and which is one without the second. This proposition he said cannot be doubted by the human being, intellectually in a sense came to be formulated most robustly by Spinoza.