1. 1 Logic isthe processof usingargumentstoarrive at the truth or falsityof a particularconclusion,
throughreasoning.The reasoningprocessusediseithergoodorfaulty,resultinginsuccessful(validand
sound) or unsuccessful(unsound) arguments.Logicisoftenusedwithinthe discipline of philosophy,but
isalso seenwithinthe fieldsof science,politics,andlaw.Continuereadingbelow tofindoutmore about
the definitionof logic,particulartypesof logic,andimportantusesof logic.
2 Deductive Versus Inductive Reasoning
Deductive reasoning is most often seen within formal logic. It occurs when an argument uses a
general rule to argue for a specific instance. For example, "Every human being will die at some
point. Fred is a human being. Therefore, he will die at some point." Deductive arguments are
able to be evaluated for validity and soundness. If there is no instance able to be imagined in
which the conclusion is false while the premises are true, the argument is valid. For example, if
there is no way to imagine Fred not dying at some point, if he is a human being, and all humans
do, in fact, die at some point. A deductive argument is sound if it is valid and the content of its
premises are true.
Inductive arguments, which are often used in informal logic, use specific instances to argue for
the adoption of general rules. For example, "I have only seen white birds since I moved to
Toronto six months ago. Therefore, it is likely that all birds in Toronto are white." These
arguments are not as definite as deductive arguments, and are unable to be defined as completely
valid or sound; only the likelihood of validity or soundness is able to be suggested. For example,
there is a good chance the conclusion of the above argument is true, but there might be a black,
blue, or red bird somewhere in Toronto that the arguer has not viewed.
People use both accurate and faulty forms of reasoning every day without thinking about them.
However, once you understand the definition of logic, you will be able to consciously make your
arguments more logical. Unless you are working as a professional logician, mathematician, or
scientist (as science often employs formal mathematics), you will likely be making use of
informal, inductive logic more than formal, deductive logic. In order to make the conclusions
you come to using inductive reasoning more likely to be valid, make sure you base your general
conclusions on many specific examples observed over a long period of time, not just a few
examples observed over a short period of time.
3 Formal VersusInformal Logic
Formal logic is the type of logic most frequently employed by philosophers and logicians. It is
more concerned with the form of an argument than the argument's content. Arguments within
formal logic use rules such as those espoused by Aristotle (described above), and they are
divided into one or more premises and a conclusion. They often appear in symbolic form, such
as, "If A, then B. If B, then C. Therefore, if A, then C." The logical progression of this argument
is more important than what A, B, and C actually represent.
Informal logic, while concerned somewhat with form, is more concerned with content. This type
of logic is often found within politics, law, and journalism, and arguments using informal logic
are written using common language, not symbols. Logicians who study informal logic evaluate
the verbal arguments used, and attempt to come up with ways to improve them.

2. What are the Fundamental Principles ofLogic?
The task of logic is to study the principles underlying the validity deductive arguments and the
strength of inductive arguments.
Since not all deductive argument are valid, we need to know the principles that ensures a valid
argument to be valid and in valid argument to be invalid. It has been suggested that the
arguments that satisfy or conform to the laws or principles of logic are valid and arguments that
do not do so are invalid. In other won validity amounts to not violating any law of logic.
Logic deals with these principles and also we their interrelation. Out of the various laws of logic
there exists three fundamental principle namely, (I) the law of identity, (ii) the law of
contradiction (or the law of non-contradiction) are the law of excluded middle.
These are known as the laws of thought or fundamental principles logic. In calling these as laws
of thought, there is a danger of interpreting them as psychological laws concerning mental
processes of thinking. This would be a misunderstanding of their true nature. These are not
descriptive laws. They do not tell us how people think. Rather these are prescriptive in nature.
They tell us how one should think or, more precisely, how one should reason. So instead of
calling them laws of thought, it is better to call them principles of logic.
These three laws are considered as fundamental or basic in the sense that any correct or good
argument must conform to these laws. This means that these laws are presuppositions of a good
argument.
What are the fundamental laws of logic?
Answer1. Law of Identity
2. Law of contradicting
3. Law of the excludedmiddle
4. Law of SufficientGround
A. Law of conservationof mass- mass isneithercreatednordestroyedduringanordinarychemical
reactionor physical reaction.
B. Law of definite porportions- achemical compoundcontainsthe same elemtentsinexactly
the same proportionsbymassregardlessof the sample of the source of the compound.
C. Law ofmultiple proportions- if twoor more differentcompoundsare composedof the same
twoelements,thenthe ratiosof the massesof the secondelement,combinedwithacertain
mass of the firstelementisalwaysaratioof small whole numbers

3. There are many different dimensions that define "a logic". Some key ones:
 Propositional vs predicate. Propositions are bare logical terms: in "if P then Q", P and Q
are propositions. Predicates are more general, e.g. in "if father(X,Y) then parent(X,Y)",
"father" and "parent" are predicates, and X and Y are variables.
 Order. In first-order logic, the variables can't denote predicates. In second-order logic,
the variables can denote predicates, so the logic can talk about itself more easily. There
are higher orders beyond that.
 Modes. Ordinary predicate and propositional logic cover "existence" and "universality"
(really, flip sides of the same coin), but other modes can cover things like "Jo believes
that..." or "It is possible [or necessary] that..." or other variants.
 Time: temporal logics are another kind of modal logic
 Probability
 Ternary and other multi-valued logics
 Negation. There are many different interpretations of the proposition "not x": first order,
negation-as-failure, paraconsistency, well-founded semantics, etc.