Here is a sentence almost every GST 212 student gets wrong in the first week: “That argument is true.” In logic, arguments are never true or false — only valid, invalid, sound or unsound, while truth and falsity belong to the individual statements inside them. That one distinction quietly decides a surprising share of your marks, and it captures exactly the kind of precise, rule-based thinking this course rewards. This page is a student-written study companion for GST 212 – Philosophy, Logic & Human Existence, the compulsory General Studies course for 200 Level students in the second semester.
What makes GST 212 high-yield is that almost nothing here is open to opinion: definitions, the three laws of thought, the parts of an argument and the rules of definition are fixed, testable facts you can simply lock in and reproduce on exam day. The summaries below turn the syllabus into plain-English notes — what logic is, the laws of thought, the nature of arguments, how to identify and analyse them, and how to define terms correctly — with original practice questions and worked answers so you can confirm each idea has actually stuck. The complete study workbook sits in the interactive reader at the end as a free bonus to the notes on this page.
- Course: GST 212 – Philosophy, Logic & Human Existence
- College / Department: General Studies (compulsory for all colleges)
- Level / Semester: 200 Level, Second Semester
- Topics covered: What logic is (definitions, aim, value & types), the three laws of thought, the nature of arguments (premises, conclusions, validity & soundness), identifying & analysing arguments, and definition (types, purposes & rules)
- Best for: Continuous assessment + final exam revision
Topics Covered in GST 212 – Philosophy, Logic & Human Existence
1. What Logic Is
Logic is the branch of philosophy that studies the principles and methods for telling good (correct) reasoning from bad (incorrect) reasoning — in short, the study of how we evaluate arguments. Different scholars phrase it differently — Copi and Cohen call it the study of the methods and principles used to distinguish correct from incorrect reasoning, Bello speaks of distinguishing good arguments from bad ones, and Hurley describes it as the organised science that evaluates arguments — but they all emphasise the same core idea: logic deals with thinking and the rules that guide it.
The aim of logic is threefold: it gives us criteria for testing whether an argument is good or bad, valid or invalid, sound or unsound; it develops a system for evaluating the arguments other people make; and it provides techniques to guide us when we construct arguments of our own. Logic matters far beyond philosophy too — it is central to mathematics, linguistics, law, engineering and computer science — and it comes in several types: informal, formal, symbolic, propositional, predicate, inductive and mathematical. Exam tip: if you can recite one clean definition, list the three aims, and name three types of logic, you have already covered what most opening questions on this topic actually demand.
2. The Laws of Thought
The laws of thought are the three basic principles of correct reasoning, and each can be written in a compact logical form where p stands for any statement and ~ means “not.” The Law of Identity (p ⊃ p) says that if a statement is true, then it is true — every statement is identical with itself. For example, if “It is raining” is true, then it is true; the statement does not quietly change its meaning halfway through an argument. The Law of Non-Contradiction says no statement can be both true and false at the same time, so any statement of the form p · ~p is self-contradictory and therefore false. You cannot hold that “Buhari is the President of Nigeria” is true and at the very same time hold that “Buhari is not the President of Nigeria” is true — to do so is to contradict yourself.
The Law of Excluded Middle (p ∨ ~p) says every statement is either true or false, with no middle ground: if a statement is not true, then it is false. The statement “It is raining” is either true or false — there is no third option. These three laws are the foundation on which valid reasoning rests. Exam tip: because examiners love asking you to match a law to its symbol or to illustrate it, drill all three on three fronts at once — name, plain meaning, and symbolic form — with a one-line example attached.
3. The Nature of Arguments
To a layman an “argument” is a verbal dispute or quarrel, but to a philosopher it is something far more precise: a set of declarative sentences split into two parts — one or more premises and a conclusion — where the premises give support for accepting the conclusion. The basic building block is the proposition: a declarative sentence that has a truth value, meaning it can be either true or false. Note carefully that individual propositions are true or false, but arguments themselves are never called true or false — they are valid or invalid, sound or unsound. There must also be a genuine relationship between the parts: “Black is beautiful. Kunle is a fine man. Therefore the car is very fast” is not an argument at all, because the propositions are unconnected, whereas “All men are mortal. Socrates is a man. Therefore Socrates is mortal” is a real argument because the premises support the conclusion.
A valid argument is one in which, if the premises are true, the conclusion cannot be false; an invalid argument is one in which the premises may be true yet the conclusion false. A sound argument goes further: it is valid and all of its propositions are actually true. Arguments are also classified by how strongly the premises support the conclusion: a deductive argument offers full support, so accepting the premises forces the conclusion, while an inductive argument offers only partial support. Formal arguments such as Modus Ponens and Modus Tollens take a fixed shape, while informal arguments appear in everyday language. Exam tip: never let “valid” and “sound” blur together; validity is purely a question of structure, whereas soundness piles on the extra demand that the premises also be true in reality.
4. Identifying & Analysing Arguments
There are two reliable ways to identify an argument. The first is by spotting indicator words, the signal words that tell us we are dealing with an argument and reveal which part is which. Conclusion indicators include therefore, wherefore, thus, consequently, accordingly, hence, so, we may infer, we may conclude and it follows that. Premise indicators include since, because, for, as, follows from, as shown by, for the reason that, inasmuch as and in view of the fact that. The second method is the two-question test: ask “What position are we asked to accept?” — the part that answers this is the conclusion — and then “Why are we asked to accept it?” — the part that answers this is the premise.
To analyse an argument you separate it into its parts, writing out the premises first and then stating the conclusion clearly. Take the argument: “All physicians are university graduates, so all members of the Nigerian Medical Association must be university graduates, since all members of the Nigerian Medical Association are physicians.” The two premises are “All physicians are university graduates” and “All members of the Nigerian Medical Association are physicians,” and the conclusion (flagged by “so”) is that all members must be university graduates. Notice that indicators can sit in the middle of a sentence, and the conclusion is not always stated first — which is exactly why the two-question test is such a useful backup. Exam tip: a labelled layout — Premise 1, Premise 2, Conclusion — scores far better than a rambling paragraph, so make that clean breakdown your default answer format.
5. Definition
We constantly need to look up the meaning of new words or to give clear definitions of the concepts we use, so logic studies definition formally. Two key technical terms matter: the definiendum (the concept or word being defined) and the definiens (the group of words used to supply its meaning). There are six recognised types of definition. A stipulative definition introduces a brand-new use for a term and sets how it should be employed; a lexical definition reports the established, dictionary meaning of a word already in use; a precising definition reduces the vagueness of a borderline term (such as fixing exactly who counts as “youth”); a theoretical definition aims at a theoretically adequate account of a disputed concept within a discipline; a persuasive definition is framed to influence attitudes or evoke emotions; and an ostensive definition defines by pointing directly to the object.
Definitions serve a range of purposes — increasing vocabulary, eliminating ambiguity, reducing vagueness, explaining a concept theoretically, influencing attitudes, and resolving disputes that arise only because people use a term in different senses. To guide good definition, five rules have been developed: (1) state the essential attributes of the species; (2) avoid circularity, so the definiendum never appears in the definiens; (3) be neither too broad nor too narrow; (4) avoid ambiguous, obscure or figurative language; and (5) be affirmative rather than negative where possible, telling us what a concept is, not merely what it is not. Exam tip: expect the six types and five rules of definition to come up as straight list questions; pairing each item with a single illustrative example lets you both name it and show what it means.
Sample Practice Questions (With Answers)
Here are a few representative questions, written in our own words, with the reasoning explained so you understand the why — not just the answer:
Q1. Define logic and state its three aims.
Answer: Logic is the branch (and tool) of philosophy that studies the principles and methods for distinguishing good arguments from bad ones — that is, for evaluating reasoning. Its three aims are: (1) to provide criteria for testing whether an argument is good or bad, valid or invalid, sound or unsound; (2) to develop a system of methods for evaluating other people’s arguments; and (3) to provide techniques that guide us in constructing good arguments of our own.
Q2. State the three laws of thought and give their logical forms.
Answer: The Law of Identity (p ⊃ p) — if a statement is true, it is true. The Law of Non-Contradiction — no statement can be both true and false at once, so p · ~p is always false. The Law of Excluded Middle (p ∨ ~p) — every statement is either true or false, with no third option. Together they are the basic principles that govern correct reasoning.
Q3. Distinguish between a valid argument and a sound argument.
Answer: Validity is about structure: an argument is valid when, if its premises are true, the conclusion cannot be false. Soundness adds a further requirement: an argument is sound only when it is both valid and all of its propositions are actually true. So every sound argument is valid, but a valid argument is not necessarily sound — it can be valid while resting on a false premise.
Q4. Using the two-question test, identify the premise and conclusion in: “The Food and Drug Management should stop all cigarette sales immediately, because cigarette smoking is the leading preventable cause of death.”
Answer: Ask “What are we asked to accept?” — that the Food and Drug Management should stop all cigarette sales immediately. That is the conclusion. Then ask “Why?” — because cigarette smoking is the leading preventable cause of death. That is the premise. The word “because” is a premise indicator confirming the breakdown.
Q5. Name any four types of definition and the two key terms used in defining.
Answer: Four of the six types are stipulative (setting a brand-new use for a term), lexical (reporting a word’s established dictionary meaning), precising (reducing the vagueness of a borderline term) and ostensive (defining by pointing to the object). The two key terms are the definiendum (the word being defined) and the definiens (the words used to supply its meaning).
Q6. Explain the difference between a deductive and an inductive argument, with an example of each.
Answer: In a deductive argument the premises give full support, so if you accept them you cannot reject the conclusion — for example, “All men are mortal; Socrates is a man; therefore Socrates is mortal.” In an inductive argument the premises give only partial support, so you may accept them yet still reject the conclusion — for example, “Abacha was a dictator and Babangida was a dictator, therefore all military heads of state are dictators.” The key contrast is the strength of support: necessity in deduction, probability in induction.
Q7. What is a proposition, and why can an argument never be called true or false?
Answer: A proposition is a declarative sentence that has a truth value — it is the kind of statement that can be either true or false, such as “It is raining” or “Nigeria is a black nation.” Truth and falsity are properties of individual propositions, not of arguments. An argument is a relationship between propositions — premises offered in support of a conclusion — so it is assessed as valid or invalid and sound or unsound, never as true or false.
How to Study GST 212 Effectively
- Master the vocabulary first — logic is a precise subject, so know exactly what terms like proposition, premise, conclusion, valid, sound, definiendum and definiens mean before anything else.
- Learn each law of thought as a trio: its name, its plain-English meaning, and its symbolic form (p ⊃ p, p · ~p, p ∨ ~p) — then test yourself with a quick example of each.
- Practise breaking real sentences into Premise 1, Premise 2 and Conclusion, using both indicator words and the two-question test until it becomes automatic.
- Keep paired concepts side by side — valid vs. sound, deductive vs. inductive, conclusion indicators vs. premise indicators — because most exam questions test the distinction, not the term alone.
- Turn lists (six types of definition, five rules of definition, types of logic) into memorised sets you can reproduce, with one short example attached to each item.
- Understand the summaries here first, then read the full workbook in the reader below and attempt the practice questions from memory before your exam.
Download the Full GST 212 Practice Workbook
The notes above already cover the syllabus, but if you want everything in one place, the full GST 212 – Philosophy, Logic & Human Existence workbook is loaded in the reader just below — definitions, side-by-side comparison tables, and step-by-step worked arguments for each topic. Flip through it right here on the page, or save a copy so you can keep drilling the laws of thought and argument breakdowns offline in the days before your paper.
Frequently Asked Questions
Is this GST 212 material free?
It is — there is no paywall, sign-up or fee here; the GST 212 notes, practice questions and downloadable workbook are all open to any student who needs them.
Do I need any maths or prior philosophy to follow the symbolic forms (p ⊃ p, p · ~p, p ∨ ~p)?
No prior philosophy or special maths background is assumed. The symbols are just shorthand — p stands for any statement and ~ means “not” — so once you read each law in plain English first and then attach its symbol, the notation becomes a memory aid rather than a hurdle. Treat the three laws of thought as your starting point before moving on to arguments.
Will these exact questions appear in my exam?
They will not. Everything in the practice set was written from scratch for revision, so use it to rehearse the reasoning and phrasing — not as a forecast of the questions your lecturer will actually set.
What is the best way to revise GST 212 quickly?
Start with the topic summaries to build your foundation, nail the key definitions and the three laws of thought, then practise breaking sample arguments into premises and conclusion. Finish by attempting the practice questions from memory and reading the full workbook in the reader below.
About this resource: All summaries, explanations, study tips, and practice questions on this page were written, paraphrased, and adapted by the EverythingABUAD student team to support exam revision. This is an original study aid, not an official ABUAD document, and it is not a prediction of any future exam.
