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02 - Reasoning, Logic, and Uncommon Sense


Something I see used a lot from pretty much everyone is "common sense". I dislike this term personally. The reason is that if sense was common, we wouldn't have so many unsensible people.  I have come to the conclusion that:
-Common sense is common but not sensible
-Common sense is uncommon but sensible

I don't think that common sense exists.


​The reason I say this is the problem many people have with understanding what logic is. It seems like an obvious thing. Logic is being logical, right? But what does that mean? What does that really mean?

Here's the issue. Many people I've seen think that they're logical when they aren't. How can logic be subjective? It isn't subjective, so how is it being used as such? It's because everyone thinks they're logical, and if they're logical then what they already think and how they think must, therefore, be logic. If everyone's logical, then the term loses all meaning as we know many people lack simple logical thought.

If you combine these two things together: everyone thinking they're logical, and common sense being something everyone thinks they have, you have the perfect conditions for being justified in any belief you already have, or believing things which you want to believe.


​One of the most basic philosophical ideas in terms of reasoning is the notion that if A = B, and B = C, then A = C. That's good simple reasoning. That's very basic logic. Let's look at an example of how this can be used correctly deductively.

A) All cars are red > B) I have a car > C) My car is red

Here's an example of it being used incorrectly.

A) I have a car > B) Some cars are red > C) I have a red car

There's a clear detachment of logic here. To put it in a way to make it more obvious, this is like saying:

A) I once farted at work > B) Someone accused me of farting > C) I therefore farted

You can see the detachment of logic in this circumstance because you or your alternative thinker friend has no bias clouding their judgment. No one has an emotional stake in me farting or not farting. I hope you can see how the above example is not a logical assumption to make. If you can't apply that to the original example, then it would be worth reflecting on what biases you're clinging on to.

A = B and B = C therefore A = C is equivalence. If someone's logic doesn't follow this when making statements of equivalence, that is called a false equivalence.

I've debated someone on clairvoyance and psychic powers who conflated these outlandish claims with the very reasonable practice of meditation, yoga, and breathing exercises. Their illogical argument went something like this:

A) Meditation, yoga, and breathing exercises help the mind > B) People practicing these things claim to be clairvoyant > C) Clairvoyance and psychic powers are something that can be achieved.

In this debate, the defense to criticism was the history of yoga and meditation being used to hundreds of years, while staying clear of justifying clairvoyance and psychic powers. Any defense was exclusively "try it for yourself", and other forms of "do your own research". In the coming pages, you will see why this response is so problematic as the burden of proof is not met and allows for unfalsifiable and unjustified beliefs.

A common method for forming arguments is :
A = true
B = true

A + B = C

For example:
A) Politicians are corrupt

B) X is a politician

C) X is corrupt

Or to put it another way:

The assumption is made that A and B are true. If A and B are not true in their entirety, then the argument is flawed.

Here's another example:

A) Liberals like socialist policies
B) Communism is a form of socialism
C) Liberals are communists

Here's another example:

A) Conservatives support nationalistic ideas

B) Nationalism breeds racism

C) Conservatives are racist

Both of those arguments are ridiculous. They're propagated on unjustified assumptions that are clearly deeply flawed.


As the name suggests, this is the logic of inferring through deduction. On LiveScience they have a good article on the difference between deductive and inductive reasoning.

"Deductive reasoning usually follows steps. First, there is a premise, then a second premise, and finally an inference. A common form of deductive reasoning is the syllogism, in which two statements — a major premise and a minor premise — reach a logical conclusion. For example, the premise "Every A is B" could be followed by another premise, "This C is A." Those statements would lead to the conclusion "This C is B." Syllogisms are considered a good way to test deductive reasoning to make sure the argument is valid."

For example:
A) All humans die
B) I am a human
C) At some point, I will die

"It's possible to come to a logical conclusion even if the generalization is not true. If the generalization is wrong, the conclusion may be logical, but it may also be untrue. For example, the argument, "All bald men are grandfathers. Harold is bald. Therefore, Harold is a grandfather," is valid logically but it is untrue because the original statement is false."

This highlights the limitations of logic. Something being logical or even just appearing logical doesn't mean the argument is correct. This is part of why people using logic or their own logic as the entirety of their reasoning behind an argument is deeply flawed.


As the name suggests, this is inferring through induction. A more simplistic way to explain it would be to draw a conclusion from a set of observations.

"An example of inductive logic is, "The coin I pulled from the bag is a penny. That coin is a penny. A third coin from the bag is a penny. Therefore, all the coins in the bag are pennies."

Even if all of the premises are true in a statement, inductive reasoning allows for the conclusion to be false. Here's an example: "Harold is a grandfather. Harold is bald. Therefore, all grandfathers are bald." The conclusion does not follow logically from the statements.

Inductive reasoning has its place in the scientific method. Scientists use it to form hypotheses and theories. Deductive reasoning allows them to apply the theories to specific situations."

For example:
A) A group of men says something racist

B) The men are all white

C) All white men are racist

Or if you want to go to a particularly dangerous area you can use inductive reasoning for some deeply troubling assumptions:

Using the Bureau of Justice and Statistics:

A) 52.2% of homicides are committed by black people

B) Black Americans account for 12.3% of the population
C) Therefore, Black Americans are much more murderous than whites

If this looks dangerously simplistic and ignorant, it's because it is. This isn't illogical in terms of inductive reasoning. If anything this demonstrates the huge flaw in inductive reasoning, because it allows for some massively misleading assumptions.

While A and B are correct, the conclusion (C) ignores the following factors (which we will later explain under cofounding variables)

-Victims by race
-Perpetrators by socio-economic status
-Perpetrators by demographic
-Perpetrators by age
-Perpetrators by gender

-Police bias towards race

-Education by perpetrator socio-economic status

For the record, I've debated someone who used this exact argument during the Black Lives Matter protests over the death of George Floyd. Her argument was troublingly oversimplified and dangerously ignorant. In her mind, that's a perfectly logical argument to make. It is not.

There are many many things you could and should take into account when talking about things like this.

Here's another flawed argument using inductive logic:

According to the NHS website:

"An estimated 9,040 people were killed or injured when at least one driver was over the drink-drive limit. This is 5% of all reported road casualties and is the highest number since 2012."

With inductive reasoning you would be justified in saying:

A) Crashing a car can cause death
B) 95% of drivers were not drunk
C) Therefore, it is safer to be drunk while driving

This is obviously false no matter what way you look at it. Simple induction can lead to some very wrong and dangerous conclusions.


This is quite different from inductive and deductive reasoning in that a conclusion is the product of probability instead of inferring an absolute conclusion. While with inductive or deductive reasoning you would pose that C is true, with abductive reasoning you would simply say that C is most likely.

"Abductive reasoning usually starts with an incomplete set of observations and proceeds to the likeliest possible explanation for the group of observations, according to Butte College. It is based on making and testing hypotheses using the best information available. It often entails making an educated guess after observing a phenomenon for which there is no clear explanation. "

Or as Merriam Webster puts it:

"Basically, it involves forming a conclusion from the information that is known. A familiar example of abduction is a detective's identification of a criminal by piecing together evidence at a crime scene. In an everyday scenario, you may be puzzled by a half-eaten sandwich on the kitchen counter. Abduction will lead you to the best explanation. Your reasoning might be that your teenage son made the sandwich and then saw that he was late for work. In a rush, he put the sandwich on the counter and left."

This is not above misuse, either. This is (I think) one of the misuses which propagate bad ideas. In order to use abductive reasoning effectively, you need to be able to weigh up evidence correctly and come to a  reasonable conclusion. This relies on the assumption that the person using abductive reasoning:

-Knows what evidence even is
-Will apply proper weight to said evidence

-That biases will not interfere with the evaluation of information

Here lies the crux of conspiracy theories. All information that supports the theory is evaluated with a very low standard of what evidence is, and as such many pieces of "evidence" aren't even evidence, more weight is applied to information that supports the conclusion and anything else is underweighted which is a consequence of that bias.

With inductive, deductive, or abductive reasoning you can make perfectly logical arguments that are fundamentally flawed. Logic on its own is not enough to form a coherent argument, and that's assuming that logic is actually being used in the first place.

Arguments propagated on logic are usually by people who don't understand the limits of the type of logic they claim to be utilising. So how can we be sure that we are correct if logic alone isn't enough to form an opinion?

You can learn:
-What constitutes evidence and what doesn't
-What biases exist and how to avoid them

-How to fact-check sources

-How science works and how to read studies

-How to reverse your own logic against your argument

This isn't a definitive list. The journey to understanding is a long and gradual accumulative process. It never ends and all we can do is hope to be a little smarter and a little more informed than we were yesterday.


Inductive Reasoning
A) All cars I see are red > B) My dad bought a car > C) That car is red

Deductive Reasoning

A) All cars are red > B) My dad bought a car > C) That car is red

Abductive Reasoning

A) Most cars I see are red > B) My dad bought a car > C) His car is probably red

That's it for now. Moving on to the next section: Philosophy - Logical Fallacies

Honestly Seeking Truth Narratedby Bobby
00:00 / 03:20
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