LOGIC AND LEGAL REASONING
INTRODUCTION
Sir Edward Coke in 1628 in “Commentary Upon Littleton”, said: “Reason is the life of the law; nay, the common law itself is nothing else but reason”.However, in 1897 Oliver Wendell Holmes, in “The Path of the Law”, was quoted saying: “The life of the law is not logic; it is experience. The felt necessities of the time, the prevalent moral and political theories, intuitions of public policy, avowed or unconscious, have had a good deal more to do than the syllogism in determining the rules by which men should be governed.”
In writing judicial opinions judges as well as other lawyers find themselves required to justify their arguments in a legal language which reflects logic and proper reasoning. The first kind of reasoning started long time ago during the Aristotle times (384 -322 BC) and was more based on scientific reasoning and therefore on rules or theorems, just like reasoning in mathematics or science
In Prior Analytics, Aristotle explains the syllogism as “a discourse in which, certain things having been supposed, something different from the things supposed results of necessity because these things are so.”
Aristotle defined the main components of reasoning in terms of inclusive and exclusive relationships. These sorts of relationships were visually grafted in the future through the use of Venn diagrams. Besides Prior Analytics, Aristotle’s other major writings on logic include Categories,On Interpretation and Posterior Analytics. In these works, Aristotle discusses his system for reasoning and for developing sound arguments. After Aristotle there developed different forms of reasoning and styles, especially in natural science and philosophy subjects.
FORMS OF REASONING: LOGIC
Reasoningdenotes the act of thinking or telling about something in a logical manner or way. It is the way of drawing inferences or conclusions through the use of reasons. Logic means a branch of philosophy dealing with correct reasoning, describing relationships among propositions in terms of implication, contradiction, contrariety, conversion, etc. It is the study of the methods and principles used in distinguishing correct from incorrect reasoning. It is a descriptive attempt to separate good reasoning from bad reasoning.
It is the science of “good reasons”. The basic components of logic mostly used in legal reasoning are syllogism, analogy and distinguishing. Distinguishing is normally regarded as the antithesis of analogy
SYLLOGISTIC REASONING
• A syllogism is a kind of logic used in legal reasoning through utilization of an argument with two premises and a conclusion; The word “Syllogism” originates from Latin “syllogismus”, later from Greek “syllogismos “ meaning inference, conclusion, computation, calculation, bring together, premise, conclude, "think together“, reckon with reason. A Syllogistic argument consists of:
• A syllogism which is a systematic and ordered set of statements,
• The statements are connected by rational inferences,
In a syllogistic argument or sentence there is always a qualifying word, a subject and a predicate. The conclusion is a statement which tries to prove or establish the truth. The first two statements contain assertions of which the concluding statement tries to prove their “truthfulness”. The first statement provides a major premise .The second sentence provides a minor premise. Syllogisms is used in scientific reasoning where it may be represented using the following three-line structure, in which A, B, and C stand for the different terms:
• All A are B.
• All C are A.
• Therefore, all C are B.
• Another way of saying the same thing is as follows:
• If A = B
• and C = A
• then C = B
Notice how the "A" functions as a kind of "middle" for the other terms. You could, for instance, write the syllogism
• If C = A = B, therefore C = B.
• An example of a syllogism in legal reasoning may be as follows:
• Major premise: “All men are mortal”
• Minor premise: “All Adams are men”
• Conclusion: “All Adams are mortal”.
• Another example may be:
• Major premise: “All animals have four legs”
• Minor premise: “All dogs are animals”
• Conclusion: “All dogs have four legs”.
Note:Normally the major premise and the conclusion are normative in nature and the minor premise is an expression of fact. Through syllogistic reasoning judges test the validity of facts in the case at hand with the rules (ratio decidendi) already made in precedent cases. Therefore rules in precedent cases are considered as major premises,
• Material facts in the case at hand are considered as minor premises;
• A conclusion made out of the two premises is a decision reached which will be part of a new rule of the case at hand. Therefore syllogism assists the court in determining good and bad reasoning in order to arrive at a logical decision. Also syllogisms may be used in writing or crafting codes or pieces of legislation where you have a major premise which expresses the general internal concept of the legal provision, followed with different categories or situations in which the relevant provision of law may apply as minor premises then followed with a conclusion which accommodates both specific as well as general situations of the provision.
DEDUCTIVE AND INDUCTIVE LOGIC
• Both deductive and inductive logic are concerned with the rules of correct or good reasoning. While deductive logic reads to establishing a conclusive inference or valid reasoning, inductive logic deals with soundness of inferences for which the evidence is not conclusive. In deductive reasoning you have a major premise, which denotes an established principal rule and an existing case or situation (minor premise) and then you are drawn to make a conclusive inference from the two premises. The conclusive inference is said to have been “deduced” from the two premises. Therefore in deductive reasoning you have a major premise of which is used to apply to it the facts of the case at hand then a conclusion is made as a result of an inference drawn from the logical consideration. In deductive reasoning rule making start from the given (the known rule) and then the reasoning starts by applying the fact of the case at hand and finally a conclusion is drawn out. This is known as “a closed system of thinking”.
SORTIES
• In deductive reasoning, the reasoning is based on one major and one minor premises as the basis of reasoning. When the same closed system of reasoning is based on more than one premises and a conclusion is made after considering more than one premises, this kind of reasoning is known as “sorties”. For example, a rule to be made on robbery contains a major premise on theft as well as on breaking and entering.
More than One Major Premises
– If any person breaks and enters in the premises of another person (1stmajor premise) and he dishonestly takes out the possession the property of that other person without his consent (2ndmajor premise), commits robbery and shall be….
– A did break and enter into the house of B and took his property without his consent (minor premise).
– Therefore A has committed robbery (conclusion).
• Major Premise : Murder is the unlawful killing of a human being with malice aforethought.
Minor Premise 1: Joseph shot and killed Henry
Minor Premise 1: Joseph shot and killed Henry
• M. Premise 2: Joseph had no lawful justification or excuse to kill Henry
• M. Premise 3: Henry is a human being
• M. Premise 4: Joseph killed Henry with malice aforethought.
• Conclusion:Therefore Joseph is guilty of murder.
Merits of Deductive Reasoning
Powerful. Deductive arguments are very powerful because they make use of valid forms of deductive arguments where the major premises must be true (in most cases they are based on a well founded precedents), if the minor premises are true (proofs of fact).
Simple method. From a few basic facts of human nature, a number of inferences can be drawn by logical reasoning.
Substitute for experimentation. Since it is not possible for legal investigators (lawyers)to conduct controlled experiments with the legal phenomena in a laboratory. They normally fall back upon deductive reasoning.
Actual and exact. The deductive method lends for the generalizations which are accurate and exact otherwise they will fail to meet the tests of being lofical.
Demerits
1. Requires high degree of logic and reasoning. Not everyone can use deductive method successfully and even many experienced legal researchers are trapped by faulty reasoning, thus ending up in making fallacies.
2. Danger of building inapplicable models. If the researcher confines only to abstraction, his model may be logically beautiful but it may be far away from real life.
3. Valid under settled conditions. The conclusions arrived at by deductive reasoning are valid only under undisputed positions of law.
The major premises must be valid, if the conclusions are to be hold.
4. Not applicable to all types of cases. Deductive method can be applicable to the limited cases only, normally easy cases. It may be difficult to apply in hard cases.
INDUCTIVE REASONING
• In situations where there are no laid down rules or where judges are doubtful of the legitimacy of the laid down rules, judges are compelled to reason in a reverse, that is, from particular situations to general rule making. Typically inductive reasoning is reasoning from particular to general but the term may be used in a broader sense to include all kinds of reasoning of which the premises support, but do not compel, the conclusion.
• In an inductive reasoning the judge is not clear of the governing rule, he uses existing empirical data or statements which he generates through experience or sources of knowledge to establish a general rule, which he later uses to a particular situation. For example, consider the reasoning by Brett MR in Heaven v. Pender . Inductive reasoning involves a process collecting data, synthesizing them before making a general conclusion, just like the way research in natural sciences is conducted.
• Premise I: In case A, elements X, Y and Z were present and plaintiff won.
• Premise 2: In case B, elements X, Y and Z were present and plaintiff won.
• Premise 3: In case C, elements X, Y and Z were present and plaintiff won.
• Conclusion: In all cases where elements X, Y and Z are present, plaintiff should win.
Merits and demerits of Inductive Method
1. More realistic. This method is more realistic because it studies the changes in conditions surrounding the social activities of man and their effect on social activities are analyzed and displayed,
2. Possibility of verification. The method is more useful because its propositions can be tested and verified easily.
3. Proper attention to complexities. This reasoning takes full note of the complex relationship found in actual life and examines them carefully.
4. Dynamic approach. This method takes into consideration the changeable nature of assumptions in its analysis.
Demerits of Inductive Method
1. It is a difficult method. This method cannot be used by beginners, it is normally used by experienced lawyers because it is impossible for an ordinary lawyer to collect facts, study them and derive some conclusions out of them.
2. Danger of bias. The propositions obtained through this method are based upon data collected by individual investigators.
Therefore, there is a danger of investigator’s bias entering into propositions.
3. Limited scope of verification. Since the propositions obtained through this method are based on a few facts, the universal applicability of these propositions is always in doubt.
4. Limited use in socio-legal studies. This method is commonly used for lifeless objects of the physical science. In socio-legal studies, we study a man’s problems it may be of little application that is why it is normally used in hard cases and by few judges.
ANALOGICAL AND DISTINGUSHING REASONING
An analogy means a comparison between two things. . An analogy looks at complex subjects and simplifies them through comparison. ,The simplified or more familiar aspect of an analogy helps a reader to understand the more complex concept and be able to make a conclusion or inference on complex concept.
• Therefore analogyis reasoning from particular to particular and may be from more complex situations to more simpler or already known situations..It is reasoning by examples, reasoning through comparing situations in precedent cases whereby similarities or differences with a case at hand assist the judge to make a legal opinion of the case at hand. .An argument from analogy begins with a comparison between two things, X and Y. It then proceeds to argue that these two things are alike in certain respects, A, B and C, and concludes that therefore they are also alike in another respect, D, in which they have not [previously] been observed to resemble one another. , Arguing by distinguishing, on the other hand, is demonstrating the dissimilarities in judicial cases and other premises. It is the antithesis of arguing by analogy. Arguing by analogy and arguing by distinguishing are thus two important elements in testing the premises and conclusions of deductive and inductive legal reasoning, since the facts and law of legal precedent are seldom identical to any subsequent legal issues
