Empirical sciences
Empirical sciences are sciences that gain knowledge through observation and experience — that is, by collecting data from the real world through the senses (seeing, measuring, experimenting, etc.).
A normative text
A normative text is a text that tells people how things should be, rather than just describing how they are.
It expresses norms, values, or rules — giving guidance, recommendations, or obligations.
Valid arguments
An argument is valid if it’s impossible for the conclusion to be false if all of the premises are true. But this condition can be fulfilled even if the conclusion and some premises are in fact false. Here is such an example where the conclusion would be guaranteed to be true if all premises were true, but where both the conclusion and a premise are in fact false:
P1) Frankfurt is in Germany or Paris is the capital of Italy.
P2) Frankfurt is not in Germany.
C) Paris is the capital of Italy.
Sound Arguments
An argument is sound if and only if:
It is valid → the conclusion logically follows from the premises.
All the premises are true.
So, a sound argument guarantees a true conclusion.
What are Inductive arguments?
An inductive argument is one in which the truth of the premises makes the conclusion probable rather than guaranteed.
Premise: The sun has risen every day in recorded history.
Conclusion: Therefore, the sun will rise tomorrow.
What are deductive arguments?
A deductive argument is one in which the truth of the premises logically ensures the truth of the conclusion.
Premise 1: All humans are mortal.
Premise 2: Socrates is a human.
Conclusion: Therefore, Socrates is mortal.
If both premises are true, the conclusion cannot be false — that’s what makes it deductively valid.
false dichotomy
A false dichotomy is a fallacy that unfairly limits a situation to two opposing choices, ignoring other reasonable possibilities.
“You’re either with us or against us.”
→ This ignores the possibility that someone could be neutral or support parts of both sides.
Because it oversimplifies complex issues and forces a choice between extremes. It makes the argument seem stronger by hiding other valid options.
Hume’s Law
Hume’s Law states that no moral conclusion (“ought”) can be logically derived from purely factual premises (“is”) without adding a moral principle.
Fact: People often act selfishly.
Conclusion: Therefore, people ought to act selfishly.
→ ❌ This reasoning violates Hume’s Law because it moves from a description of what is (people act selfishly) to a claim about what should be without justification.
Analogical argument
An analogical argument claims that if Thing A has certain properties, and Thing B is similar to A in relevant ways, then B probably has the same properties.
🔹 Example:
Premise 1: Earth has life and is a planet.
Premise 2: Planet X is very similar to Earth in size, atmosphere, and temperature.
Conclusion: Planet X probably has life.
Modus tollens
If “If P, then Q” is true, and Q is false, then P must also be false.
🔹 Logical Form:
If P → Q
¬Q (Q is not true)
Therefore, ¬P (P is not true)
Modus ponens
If “If P, then Q” is true, and P is true, then Q must also be true.
🔹 Logical Form:
If P → Q
P
Therefore, Q
Statistical argument
A statistical argument draws a conclusion about a population, group, or event based on statistical evidence or observed patterns.
Inference to the best explanation
Inference to the Best Explanation (IBE) is a type of reasoning where we choose the explanation that best accounts for the evidence. Instead of proving something with certainty, we select the most plausible or likely explanation based on what we know.
