Class 1.1: Where is the Truth?

Methodology of Scientific Research

Andrés Aravena, PhD

February 18, 2022

How do you know?

Tell me…

Do you smoke?

Is it healthy?


How do you know?

Tell me…

Did you get vaccinated?


How do you know?

Do you believe in …

  • Ghosts
  • Fairies
  • Germs
  • Climate change
  • UFO’s carrying aliens
  • Atoms

How do we know what we know?

First approach

First approach: Perception

We see, we hear: Empirical Truth

We perceive the world with our 8 senses

  • Sense-Certainty
  • see to believe

But …

Are they parallel?

Are they parallel?

Which blue circle is bigger?

Which one is bigger

Which color is the dress?

Google “The Dress”, and watch “The Dress is Bloie”

How many colors

Are A and B the same color?

Black or white dots?

Do the lines cross?

Do they cross?

Is this a movie?

Does this move?

Does this move?

Does this move?

Does this move?

Does this move?

We cannot trust our senses

We can have optical illusions

Illusions are not only optical

Put one hand in hot water, the other in cold water

Then put both in warm water

Perception depends on our expectations

Have you ever seen someone that was not there?


We dream

and we don’t know that we are dreaming

Our mind cannot be trusted

When we dream, we don’t know that we are dreaming

We cannot even trust our memory

  • False memories can be implanted

  • We can experience Déjà vu

Some research about false memories

  • Michaelian Kourken “Confabulating, Misremembering, Relearning: The Simulation Theory of Memory and Unsuccessful Remembering”. Frontiers in Psychology 7 (2016) DOI 10.3389/fpsyg.2016.01857

  • The work of Elizabeth Loftus

We have Incomplete information

“The Earth is flat”

We only see part of reality

Our experience is limited

  • Our friends are like us. It seems that everybody agrees with us
  • At our scale, the Earth is flat, the mountains do not change, and atoms do not exist

Our vision is “local”

We only see our neighborhood of the network, where everybody looks like us

The Earth looks flat

  • Today some people believe that Earth is flat
  • Some people believe that old people believed the Earth is flat

Our senses can fool us

  • Optical illusions
  • Dreams
  • Incomplete information

Distrust of senses
The body is dirty, the soul is pure

Plan B: Rational view

“Truth emerges from Reason

Idea represented by

  • Aristotle
    • logic syllogism
  • Euclid
    • geometry
    • axioms
    • theorems

Both aim to Separate Essence from Accident

But people can disagree…

It is common that philosophers disagree on their reasoning

  • They start from different hypotheses

  • They use the same words with different meanings

  • Their logic may not be solid

Maths solves this problem

  • Hypothesis are clearly defined

  • Meaning of words are clearly defined

  • Uses well defined logic

At the cost of loosing contact with reality

Math is not about nature. It is all imaginary

Math only exists in our minds

Math is the ultimate Humanist discipline


Rational thinking chemically pure

  • Feelings are not important, but truth feels good

  • Beauty is not important, but truth is beautiful

  • Abstraction disconnects from details

Separate Essence from Accident

Correct reasoning is hard

The priority of our organism is

  1. Survival
  2. Save energy

So fast and gut decisions are automatic

  • Most of the time we use the cheap intuitive system
  • Rational thinking (i.e. math) is not spontaneous

Instead of thinking, we “guess” or “ask someone else”

Plan C: Truth from authority

“My dad is always right”

“Someone told me…”

Most of our knowledge comes from other people

  • Our parents

  • Our professors

  • Books

  • Scientific papers

  • Authority

“Truth from authority”

  • Medieval/feudal point of view

  • “Aristotle was the most intelligent man, he must be right”

  • Knowledge is in “The Books”

  • Catholic church was built on this premise

Political power liked it: “the boss is always right about everything”

Research Question 1

The “official” history is from a European point of view.

What can we say from the Middle-East point of view?

But how do they know?

This approach just delays the question

If our knowledge comes from someone else, how did they know what is true?

Is rationality enough?

Extramission theory of vision?

  • A theory accepted by Plato, Euclid and others
  • The eyes emit a “gentle” fire that touches the objects we see
  • We need to mix with another fire to see
    • like the sun
    • or a campfire

Geocentric model of the planets

People believed that Earth was inside crystal spheres

  • Stars were in a steel sphere
  • When we find a fallen star, it is made of steel
  • common prefix: “sider”

Fire, earth, water and air

All material is a mix of these four elements.
For example

  • Wood is made of fire and earth.
  • Burning wood separates the fire
  • leaving only earth (ash) behind

Humor theory

Excess or deficiency of any of four distinct bodily fluids (humors) influences temperament and health

  • Classic Greek, Roman, Persian and Indian (Ayurveda)
    • Blood, Yellow bile, Black bile, Phlegm
  • Hippocrates (born c. 460 B.C.E.)
  • Galen (b. 129C.E. Asia Minor)
  • Bloodletting used until the 19th century

Today: Conspiracy theories

  • Apollo moon landings were staged
  • Weather control
  • GMO research is fake

Today: Conspiracy theories

  • Roswell UFO incident
  • Area 51
  • Kennedy assassination
  • 9/11

Research Question 2

What other things are believed by smart people despite evidence on the contrary?

What Aristotle did not knew

The age of discoveries showed that the old books did not have all answers

  • What about America?
  • What about Australia?


Where is the Truth?

The Truth is Out There