An Introduction to C.S. Peirce’s Philosophy of Logic and His Logic of Science

The Necessity of Logic

According to C.S. Peirce, without logic we can never know what we think:

… logic shall teach us… To know what we think, to be masters of our own meaning, will make a solid foundation for great and weighty thought. (‘How To Make Our Ideas Clear’, 260)

The genius of a man’s logical method should be loved and reverenced as his bride, whom he has chosen from all the world. (‘Fixation of Belief’, 257)

Logic, according to Peirce, teaches us how to be ‘masters of our own meaning’. There is a slightly post-structuralist feel to this comment. Sometimes we may not know what exactly we mean by the things we say. Our meanings, if there are such things in the first place, are not perfectly introspectable – they are not perfectly transparent. Perhaps, then, it is the expression of our thoughts that is faulty. This, however, hints at some kind of conceptual separation of thought from expression. We may not express our thoughts correctly, but this does not automatically mean that thought must somehow exist prior to or separately from our expressions. A thought is incorrectly expressed simply because there is a better expression available that can do the required job. We may know that an expression is not quite right, even without a pure thought telling us, so to speak, that it has not been expressed correctly. As Davidson put it:

Thought and talk are, in essence, the same thing.

Of course he must also include here other expressions other than actual verbal locutions.

In Peirce’s ‘Fixation of Belief’ we also have the philosopher’s emphasis on method – or, the correct or most fruitful method. This, if only this, shows a Cartesian streak in Peirce. Get the philosophical and logical method right, and much that is good and worthwhile will automatically follow.

If we do not know what we think, surely it is the case that we do not in fact think at all. We must know the contents of our thoughts, and the relations between our thoughts, if we are to think at all. The statement that we do not know what we think does not really make sense prima facie. Without such knowledge, we would not think at all. In a certain sense, logic cannot teach us ‘to know what we think’ because we must already be thinking in order to call on the services of logic to clarify our thoughts. In that sense perhaps it is the case that logic simply systematises and clarifies what we think, but doesn’t actually enable us to think. There are, however, modes of reasoning that we do not indulge in until we are ‘taught by logic’. Despite that, it must be some kind of thought itself that brings us, in the first place, to logic.

Implication, Inference and Formal Inquiry

Descartes, like Dewey, wanted a logic that could be used in epistemology and indeed other branches of logic. Logic is primarily concerned with inquiry, not abstract formal relations. Indeed even though Descartes in a sense wanted to base his overall philosophy of various deductive systems in logic, geometry and mathematics, he was not himself a keen logician, and lived at a time when logic was virtually ignored by most philosophers. In fact Descartes philosophical system cannot be seen to be equivalent to any kind of logical system that is known. However, it may well be logical in the sense in which Dewey meant by the term ‘logical’. Its primary purpose was its applicational possibilities, as well as its close relations to the various sciences.

Although logic is ultimately free from the thought processes and the minds of empirical human beings, it is still nevertheless true that we can learn from psychological research into the nature of, say, inference, simply because human minds do, at times, infer correctly. Human inferences do actually replicate the nature of pure formal inference as it occurs in the abstract realm of pure logic. Of course human beings can and do go wrong, but logic, as it were, cannot go wrong. We can make it go wrong in the sense that we can misapply or misinterpret certain logical laws or logical truths. But that is our fault, not logic’s. In that sense logic is not just a “purely formal inquiry”, it must also reflect certain psychological facts about how humans do in fact reason and use certain logical principles. If it is totally divorced from human minds and the way that human minds infer and reason, then it will become purely a “mathematical recreation”. Even if logic is divorced from the vagaries of particular minds at particular times, it is us that are supposed to utilise logic in both philosophy and our everyday reasonings. Not only that, but we may be, at times, using logic absolutely correctly. None of this matters in pure mathematics, at least in theory.

Peirce seems to be making an interesting distinction between inference and implication. The distinction seems to be that inference is a psychological process, whereas implication seems to be purely formal. Minds infer and logical statements imply. We discover the “nature of inference” by conducting a “form of inquiry” into how people reason. Implication, on the other hand, is “simply a formal relationship” between different parts of a logical system. A implies B, but John infers B from A. However, even implication is still used by minds. Even if it is a purely formal relation between two things, implications are still made use of by persons. Even if A would imply B without minds, it is still minds that note that implication, notate or express it, and use it in their reasonings. However, it is still hard to decipher whether or not Peirce meant all this from the little that is said in this particular book. I personally have never thought that inference is any more psychological a thing than implication. After all not only do we say that “So and so inferred this and that”; we also say “So and so implied this and that”, or “There is a definite implication in what so and so is saying”.

Logic’s Relation to Science

Dewey has a very particular position on logic. Logic, in his eyes, is derived from the methods and practices used in actual science. And because science is always on the move, as it were, then we should not see logical principles as

eternal truths which have been laid down once and for all as supplying a pattern of reasoning to which all inquiry must conform.

Just as science does not offer us eternal truths, neither should logic. Indeed if logic bases its principles on the methods and reasonings found in science, then this attitude to truth will evidently be the case. There is another point about logic that is worth making here. Even if logic does deal with eternal truths and principles that somehow exist mind-independently, it does not follow at all that logicians, any logicians, have access to these eternal truths and principles. Perhaps we simply haven’t discovered or arrived at all, or any, of these eternal truths and principles. We can accept that logic is in some sense an eternal mind-impendent entity, but it may not be the case that we are fully in tune, or in tune at all, with this eternal, non-spatiotemporal abstract world of logic; just as we know that there are planets out there that we know nothing about. However, we may have good reasons for believing in their existence even if we know nothing about them.

All this means that it would simply be unwise to accept any logical principle or truth as having some kind of eternal status. Such things may well exist, but we may not have a true access to them in their fullness. Having an absolutist position on logical truths and principles may prove to be highly negative in its various implications for logic itself and for all those disciplines that use logical truths and principles. Perhaps it was Dewey’s scepticism about eternal truth and principles that made him decide that logicians should base their principles, truths and methods, inferential patterns, etc., on what actually happens in science. That way we would not stick rigidly to certain logical truths or principles. Like science, logic should be fallibilist. And indeed philosophers like Quine in the 20^th century were indeed fallibilists when it came to both mathematics and logic. After all, Quine become sceptical about the truth of the law of excluded middle, or at least of its applicability, because of the finding in physics regarding quantum phenomena. And many philosophers believe that statements about the future can be neither true nor false, but truth-values must include a third value – indeterminate. Such philosophers, therefore, rejected the ancient Principle of Bivalence. We could say that certain scientists had rejected the law of excluded middle and the Principle of Bivalence long before any philosopher rejected them. These are classic examples of empirical reality having a strong effect on the sacred principles and truths of logic. Unlike the Tractatus view of logic, the ultimate relation goes from the world to logic, not from logic to the world. Indeed if logic has no necessary relation to the world, then we may in practice stick with certain principles and truths for all time. There may never be any reason to rejected these inalienable logical principles and truths. Only the world can, as it were, challenge them. And the world has repeatedly challenged the assumptions and presuppositions of logic throughout logic’s history.

Dewey brings in a typically pragmatist angle to his critique of traditional views of logic. He takes note of the successes of science. Whichever logical rules or principles science used when it scored particular successes, are the logical rules and principles that logicians should adopt, even in pure logic. And, again, science has always adopted new logical methods in their pursuits. Logic should too. Not only in the relation definitely from the world to logic, but because of the primacy of the world, the other relation should be from science to logic as well. In that case, logic in a sense seems to take a back seat when it comes to science. This isn’t so strange if one considers Quine’s position on epistemology, ontology and all the other branches of philosophy. These too, according to Quine, should take a back seat to science. There is no a priori philosophy, according to Quine; therefore there should be no fully a priori logic either. Logic is effectively no different to philosophy in these respects. Because science’s relation to the world is both more direct and more systematic, then of course logic and philosophy should “defer”, as Quine puts it, to science. Or, to use a term used mainly in the 20^th century, logic, along with philosophy, should be naturalised so that they do not systematically conflict with science and the findings of science. Just as single statements, terms, judgements, concepts, etc., are not self-sufficient, neither are the whole disciplines of philosophy and logic. Just as statements cannot truly be atomic, so too philosophy and logic as wholes cannot be atomic. Holism, of some description, goes all the way down the line. There are no exceptions or escapes.

Throughout ‘Fixation of Belief’ Peirce seems to use the terms science and ‘logic’ as virtual synonyms. In order to demonstrate their equivalence, Peirce cites the example of Darwin’s use of the ‘statistical method’ in biology:

The Darwinian controversy is, in large part, a question of logic. Mr. Darwin proposed to apply the statistical method to biology. The same thing had been done in a wildly different branch of science, the theory of gases. Though unable to say what the movements of any particular molecule of a gas would be on a certain hypothesis regarding the constitution of this class of bodies, Clausius and Maxwell were yet able, by the application of the doctrine of probabilities, to predict that in the long run such and such a proportion of the molecules would under given circumstances, acquire such and such velocities… In like manner, Darwin while unable to say what the operation of the variation and natural selection in any individual case will be, demonstrates that in the long run they will adapt animals to their circumstances. (F of B, 244)

As a non-scientist, it is interesting to note here the use of probability theory some 40 to 50 years before the birth of quantum mechanics.

As Peirce pointed out in the 19^th century, probability is at the heart of scientific laws – and all this well before the birth of quantum physics:

… scientific laws do not as a rule state universal connections, but only probabilities: the probability of ‘a’ given ‘b’. In the case of quantum mechanics… these probabilities are ineliminable… (S, 180)

Logic: Truth Not Just Validity

Which is the correct theory of logic? Peter Smith says it does not matter if the premises are true or false. What matters is the validity of the logical reasoning that follows it. Peirce, on the other hand, seems to b a logical realist. He believes that the premises must be true. More precisely, he says that ‘the question of its validity is purely one of fact and not of thinking’:

… reasoning is good if it be such as to give a true conclusion from true premises, and not otherwise. Thus, the question of its validity is purely one of fact and not of thinking. ‘A’ being the premises and ‘B’ the conclusion, the question is, whether these facts are really so related that if ‘A’ is ‘B’ is. If so, the inference is valid; if not, not. It is not in the least the question whether, when the premises are accepted by the mind, we feel an impulse to accept the conclusion also. It is true that we do generally reason correctly by nature. But this is an accident; the true conclusion would remain true if we had no impulse to accept it; and the false would remain false, though we could not resist the tendency to believe it. (244, F of B)

Perhaps this is why Peirce is different to the ‘pure’ logician. He correlates logic with science because he demands premises to be true. To be based on the facts of the world. Here we also have a kind of logical anti-psychologism that is reminiscent of Frege. We may well reason correctly. We may accept a conclusion to be the correct conclusion from given premises. However, what we think is irrelevant. We may well reason correctly, but correct reasoning is not an effect of our reasoning correctly. Correct reasoning exists independently of our thought processes. Similarly, a conclusion that we accept may be true. However, our thinking it true does not make it true. It would be true even if no one thought it were true.

Russell makes a similar claim for logical thought:

The name ‘laws of thought’ is… misleading, for what is important is not the fact that we think in accordance with these laws, but the fact that things behave in accordance with them… (73, Problems of Philosophy)

Similarly:

A similar argument applies to any… a priori judgement. When we judge that two and two are four, we are not making a judgement about our thoughts, but about all actual or possible couples. (89)

The belief in the law of contradiction is a belief about things, not only about thoughts. It is not, e.g., the belief that if we think a certain tree is a beech, we cannot at the same time think that it is not a beech; it is the belief that if the tree is a beech, it cannot at the same time be not a beech. Thus the law of contradiction is about things, and not merely about thoughts; and although belief in the law of contradiction is a thought, the law of contradiction itself is not a thought, but a fact concerning things in the world. (P of P, 89)

Here Russell articulates a position that can be called ‘logical realism’. It is realist because, in a sense, the laws of logic come from the nature of things, not from logic or thought or conventions. The law of contradiction is not about the impossibility or incorrectness of believing both p and not-p, but about the impossibility of, say, a ball being red all over and the same ball being blue all over. This is the opposite of logical conventionalism. Even in Wittgenstein’s Tractatus the direction of the logical arrow, so to speak, is from logic to world, not from world to logic. As Tractarian Wittgenstein might have put it: the world can be anyway it likes. However, because of the necessities and impossibilities generated by our logic, the world can only be a certain way for us. We see the world, as it were, through our logical spectacles. If our logic or logics were different, then it seems the world would be different – or at least it would be cognised differently, even if the world as it is in itself does not change to suit our logics. This, alone, makes Tractarian Wittgenstein a kind of logical conventionalist in that different logics make different worlds. Not only that, but the arrow always points from logic to world, not the other way around.

Of course what Russell says about things, must also be true about thoughts because the law of contradiction applies to everything, not just things and thoughts. Russell clarifies his position by saying that

although belief in the law of contradiction is a thought, the law of contradiction itself is not a thought.

It is, instead, a fact about ‘the world’ and everything in the world.

In what sense is Peirce, rather than Russell, a Kantian if he believes that thought, perception and even logical reasoning are fundamentally determined by ‘Real Things’ in the world? Doesn’t a Kantian believe that the determining process works the other way? That is, the categories of the mind shape the world?

I suppose if one sees this debate from an evolutionary perspective, which Peirce hints at, it can become dizzyingly circular. Perhaps Real Things in the world determine our Kantian categories, which in turn determine the world. If Kant had been born in the 19^th century and became a Darwinian, he might have said that the categories of the mind had their first cause in Real Things, rather than vice versa.

Abduction and Hypotheses

Whereas deductive inference infers from a small set of axioms or premises, and inductive inference from a large group of instances of a given phenomenon, abductive inference is more like a shot in the dark. When we come across a “surprising fact” we will need to explain it. Why is it surprising to us? Then we come up with an explanation of the curious fact. That explanation must serve a purpose. That is to make the curious or surprising fact non-curious or unsurprising. The explanation explains away the fact’s curious nature or its surprising nature. By explaining or understanding the fact, we take away its anomalous character. Things are only surprising or curious if we cannot explain them. This explanation of the fact, according to Peirce, would therefore be an “explanatory hypothesis”. This means that such a hypothesis is not deductively or inductively inferred from anything as such. It is not a logical conclusion, entailment or implication. It is an explanation of a given fact. The explanation itself is not thereby factual. It is a means of making sense of a given phenomenon. Another important point about Peircian hypotheses is that they come before any testing, any calculations, any experiments, etc. These things are carried out to determine the truth of the hypothesis in question. It is not the case, as many people think, that the hypothesis is formulated after the tests, the calculations and the experiments. It is not, as it were, inferred from such things. Instead the hypothesis motivates or brings about the tests, calculations and experiments, rather than vice versa. Hypotheses are essentially creative acts or even acts of intuition, in a loose sense. They are neither the logical consequence of things, nor are they derived from empirical experimentation. If I see that a town has been levelled to the ground, I will immediately formulate the hypothesis that there has been a nuclear bomb dropped on the town. I would not have formulated this hypothesis after carrying out radiation tests, or calculating the strength of the bomb, or by collecting the data of destruction to help me inductively infer that there has been a nuclear bomb. No, the hypothesis is as it were spontaneous. And even if it were not exactly spontaneous, it would still not rely on prior tests or experiments or things that I can deductively or inductively infer from them. The whole point of the hypothesis is to get the ball rolling. It is not what comes after the ball has stopped rolling.

What matters about the “explanatory hypothesis” is what it says will happen if certain experiments or tests are carried out. If the results that it conjectures do in fact happen, then the hypothesis is taken as true, if only for a given amount of time.

We first begin with abduction, however, after the acts of abduction it will indeed be the case that scientist will utilise the principle of induction. First comes the abduction, then come the tests, experiments and calculations that attempt to legitimise the abductive inference, then, all this is put together via various inductive processes. We infer from these various experiments, tests, calculations, and abductions, a single inductive inference or conclusion.

Many people seem to think that science is all about induction. In fact, it is about induction, deduction and abduction. In fact, because abductive acts come first, they could be deemed to be the most important type of inference out of the three. The abduction, or “explanatory hypothesis”, is used as a basis for further inductive inferences. It becomes a guide for later inductive processes. This means that the hypothesis says this or that, or explains this or that. Then the scientist investigates various examples or instances of these phenomena that are explained by the hypothesis. The scientist then sees whether or not it is the case that the explanatory hypothesis holds true for the many instances of the phenomenon concerned. Inductively speaking, the abduction must explain more than a single phenomenon. It must also explain every phenomenon of this type. And the different instances of this type are put together or made uniform through various inductive processes. And after all this is achieved, the scientific results will be formalised via various deductive logical systems. For example, the inductive conclusion, itself dependent on the abductive inference, may itself become an axiom or premise in an otherwise deductive logical system. If the inductively derived conclusion is true, then what will deductively follow from it? What will follow from it that we can say just by analysing the conclusion-come-premise itself? What can we deduced by simply exploring the premise’s logical grammar?

Abduction somehow explains certain observations. In other words, it is a hypothesis. Or, the other way round, from such an abductive hypothesis we may know what kind of observations to expect given pre-existing data. Unlike induction, an abductive argument will begin with some kind of generalisation:

All the beans from this bag are white.

These beans are white.

Therefore, these beans are from this bag.

The second premise moves to the particular. The conclusion, in this case, in a sense fuses the first and second premises. Because all the beans in the bag are white, these particular white beans may be from that bag. In the above example, it is not yet known where the white beans have come from. The conclusion, given the first premise, hypothesises the possibility that given all the beans in the bag are white, then these particular white beans must also be from the bag. The first premise can itself be seen as the conclusion of a previous inductive argument. From observations of many particular white beans, it was concluded that all the beans in the bag must be white. Or, to use Flach’s terms, the first premise of the abductive argument gives us the inductive “general rule”. The abductive part of the argument, as it were, will be the abductive inference that the particular white beans in front of the observer will probably be from the bag of white beans. In this instance, abduction takes over where induction left off.

Logica Utens and Logica Docens

Logic is not simply a game or a pastime, we are logical in everyday life, at least to some extent. Peirce calls this our logica utens, or ‘folk logic’:

… We all possess ‘habits’ of reasoning and inquiry: or (in Peirce’s term) our logica utens. These habits incorporate patterns of reasoning (‘guiding principles’) which lead us to accept reasonings of certain kinds. (Handout 3)

Peirce distinguishes logica utens from logica docens:

Peirce’s ‘Illustrations’ are a contribution to logica docens: the scientific or philosophical study of the guiding principles which we ought to use. (as above)

‘Folk logic’ is like common sense, but if it really were as Kantian as it sounds it would need to be universal. Absolutely not empirically-based. However, common sense or logica utens would differ markedly if we compared, say, ancient China with, say, 19^th century Germany. We all have the same perceptual tools, but could we go so far as to say that we indulge in the same kinds of reasoning? Chomsky may think that this is the case if we think of the logic of universal grammar, for example. However, on the basic scale, at the ‘folk logic’ level, we all believe in causality, in the law of non-contradiction, but also in markedly non-logical things like a flat earth or pixies. Is there part of the brain that is dealing with the logical and another part with the illogical?

P’s and Q’s as Statements and Classes

Peirce seems to interpret the symbols p and q, in ‘if p, q’, as standing for statements rather than standing for things or other kinds. In that case, if the statement ‘Tony Blair is Prime Minister’ is true, then the statement ‘Tony Blair is a politician’ must also be true. This would be a relation between the contents of expressions, rather than between objects of some description. We could say, on a conceptual view, that in the statement p the concept [Prime Minister] contains or entails the concept [politician]. Peirce’s view, ‘if p, q’ is not about an object and its necessary properties, but between the truth of p and the truth of q. Truth belongs to p only if p is a sentential statement. And in ‘if p then q’, this is not a question of the nature of p necessarily entailing the nature of q. Necessity and truth belong to statemental expressions and not objects of some kind.

Some philosophers tried to reduce the relations between propositions to the relations between classes. If there is a relation between two statements, then that must be because they share words for classes that are related, or one class in one statement is a member of the class in the other statement. In the statement ‘Tony Blair is a politician’ is related to the statement ‘Blair is a politician’ because the class has as it members Prime Ministers is contained in the second class of politicians referred to in the second and entailed statement. This means that the class of Prime Ministers has fewer members than the class of politicians. We could say that the class of Prime Ministers is contained within the class of politicians or that the class of Prime Ministers is a sub-class of the other class. The truth relation between p and q is therefore determined by the nature of the classes referred to, tacitly, in both statements. We could rephrase the two statements thus:

Tony Blair is a member of the class of Prime Ministers.

is true, therefore the statement

Blair is a member of the class of politicians.

must also be true. I would simply use the concept [concept] rather than the concept [class] in such analyses of statements. Why did Peirce reject this reduction of the relation between statements to a relation between classes?

Monadic and Polyadic Relations

It was natural for philosophers to think in terms of monadic predicates because they also thought in terms of subjects and predicates. That monadic relation was perfectly captured by subject-predicate expressions. Of course at an ontological level many philosophers also thought in terms of objects and properties which itself was matched by subject-predicate expressions. Of course there is more to the world than objects and their properties. There are also relations between objects and even between properties. To take a simple example. We cannot say all that is important about Tony Blair simply by describing his material reality and his properties. What about his relation to the British people as a whole? That relation, surely, cannot be captured by a simple predicate of a simple property. We can, however, say that Tony Blair’s relation to the British public is itself a property of him. If that’s the case, it is a very strange and abstract property. And if such relations were seen as properties of persons and object, then each object would have an indefinite, perhaps infinite, amount of attributable properties. They could not be used as simple descriptive features of objects or persons.

In dyadic predicates we can have two subjects that are, of course, related to each other in some way. For example, ‘John is a lover of Jane’. Or even ‘John is a lover of football’. The question must now be: What is the nature of these relations? What do all dyadic relations have in common apart from the fact that they are relations between two objects or persons? We could say that the love relation between John and Jane is causal. John loves Jane because he has experienced Jane and her characteristics. What if I have some kind of relation to a mathematical statement or to something I have never experienced? For example, ‘… is bigger than’ is not really a causal relation. And p implies q is certainly not a causal relation, even if we have a causal relation to that formula’s expression or notation. What could relations be if they were not causal?

With polyadic relations we have three subjects in the sentence. Three things of whatever sort are related to each other in some way. When I give an apple to John there are three objects in the relation: the apple, John, and me. Not only do I have a relation to John, I also have a relation to the apple that I give to John. We can say that the relation is “passed on” from the apple to John. I must at first have had a relation to the apple before I could give it to John. What is the relation of giving? This too seems to be causal in nature. I see the apple, pick it up and then give it to John. However, even if these actions are causal, and the objects partake of causal relations, this may not mean that the relation itself is causal. What about Peirce’s important example? This is:

…stands to…for…

Let’s fill in the blanks to make things simpler. We can have:

The Union Jack stands to Paul for mindless patriotism.

Here there is part of the relation that is clearly not causal. I may indeed have a causal relation to a Union Jack, but what about my relation to my belief that it represents or stands for mindless patriotism? This belief must in a sense by a non-causal entity that may include mental ideas, concepts, and other beliefs. Even my relation to the Union Jack may not be causal. This means that I may have a relation that is causal to a token of the Union Jack, but I still have a relation to it even when I haven’t come across a concrete one for many years. What is my relation to the type Union Jack? Perhaps the type Union Jack is an abstract object or something in my mind.

Of course the discovery or acceptance of polyadic relations was important to logic and philosophy. Just think about the nature of all sentences. Is every sentence of the form “…is bald”? Of course not. Even atomic statements are sometimes polyadic. For example, “Joe stands to Paul for cheerfulness.” Again, Joe’s relation to the people who take it for a walk is just as important as the property having a tail or the property barking.

Presuppositions and First Principles From Introspection

Peirce seems to argue that there are certain premises that we must accept in order to get started with the ‘scientific method’. He calls these ‘Presuppositions of the logical question’, or ‘guiding principles’. Without them there would be various regresses. These presuppositions are not axioms, or self-evident, or even evident premises:

The strategy is to identify those facts that are ‘already assumed when the logical question is first asked’… Let us call these facts the ‘Presuppositions of the logical question’… An argument which shows that something is true because it is a presupposition of logic or reasoning is sometimes called a ‘transcendental argument’…

This sounds like the argument against total or global scepticism. Before we can doubt anything, or one thing, we must accept at least one thing without doubt. If we did not do so, then we could not doubt at all. We can say, paraphrasing Peirce, that total scepticism

already assumes various things when the sceptical question is first asked.

What are these Peircian presuppositions?

There are such states of mind as doubt and belief. Passage from one to the other is possible. This transition is bound by rules that all minds alike are bound by.

This last presupposition is perhaps the most Kantian in character. Are these ‘rules’ equivalent to Kant’s ‘categories’? Are they, as it were, ‘laws of thought’?

An alternative view to Peirce’s position on presuppositions is of course offered:

It is obvious to introspection: we can ‘see’ that there are states that provide the first premises for reasoning and which are the direct result of the impact of ‘Reality’ upon us. Philosophical argument can show that unless there are such absolute first premises, one can have no contact with reality and no justified beliefs at all: a regress justification.

And this was the approach, of course, taken by Descartes in the 17^th century. There must be ‘absolute first premises’. If there are not, then we will be involved in various regresses of ‘justification’. Descartes found his first absolute premise in the Cogito: ‘I think, therefore I am.’ However, unlike what is written above, this first Cartesian premise or axiom has nothing to do with ‘the impact of Reality upon us’. Descartes, at this stage, was not trying to prove the existence of the world by his first premise, though that came later. He was simply making a point about total scepticism. That there are certain things that we cannot doubt. From that first premise, of course, we can move towards a proof of the external world, but Descartes’ first premise, the Cogito, had nothing to do with ‘reality’s impact on us’.

The passage above would be more like an argument given by a metaphysical realist. From the absolute premise/s we can conclude that we have contact with reality. Without such indubitable first premises, ‘one can have no contact with reality’. Not only that, but we would also involve ourselves in various regresses of justification. Such first premises, therefore, were the means for metaphysical realists to put us in direct touch with Reality. Descartes’ first premise, on the other hand, is a means to defeat global or total scepticism. Doubt about the external world is just a by-product, as it were, of total scepticism because such scepticism doubts everything. Descartes, on the other hand, attempted to show us that there are certain things that we cannot doubt. And from these things, the first premise/s, we could also infer that there were many other things that we could not, or should not, doubt. Proof of the external world would, as it were, come at the end of Descartes’ deductive system of doubt, or at least it would be a conclusion that eventually sprang from the initial Cogito.