The document discusses the foundations of knowledge, focusing on two types: sense perception and rational knowledge. It explores contributions from philosophers like Plato, Aristotle, and Galileo, highlighting the tension between rationalism and empiricism in understanding knowledge. The text also raises questions about the relationship between observation, experimentation, and the conceptual frameworks that underpin scientific inquiry.

1. THE FOUNDATION OF
KNOWLEDGE
1. Sense perception and rational knowledge
2. Plato and Aristotle
3. Galileo
4. Rationalism and Empiricism
5. The foundation of knowledge

2. Sense perception
There are two kinds of
knowledge:
And rational knowledge
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE

3. SENSE PERCEPTION AND
RATIONAL KNOWLEDGE
Through sense
perception we are
aware of the world
that surrounds us
SENSE PERCEPTION

4. We acquire sensible
knowledge through
the five senses:
Sight, hearing,
taste, smell and
touch
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE
SENSE PERCEPTION

5. Sensible knowledge is
concrete: it shows
us images (visual,
aural...) of the
things we perceive
(this flower, this
horse...)
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE
SENSE PERCEPTION

6. Sensible knowledge
seems immediate to
us: we say that we
see or hear things
directly, just as they
are
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE
SENSE PERCEPTION

7. Rational knowledge is
abstract: we create
concepts through
which we
understand the
world
RATIONAL KNOWLEDGE
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE

8. Concepts are
intermediaries
between mind,
words and things,
and between some
people and others
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE
RATIONAL KNOWLEDGE

9. That is why we say that
rational knowledge
is a mediate
knowledge
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE
RATIONAL KNOWLEDGE

10. We usually think that sense perception is
more reliable than rational because it is
immediate.
But rational knowledge provides arguments
and proofs, which we need for science
and philosophy.
SENSE PERCEPTION AND
RATIONAL KNOWLEDGE

11. THE FOUNDATION OF
KNOWLEDGE
1. Sense perception and rational knowledge
2. Plato and Aristotle
3. Galileo
4. Rationalism and Empiricism
5. The foundation of knowledge

12. Plato and Aristotle lived
around the 5th
century BC in
Athens
PLATO AND ARISTOTLE

13. Though they were
master and disciple,
they had confronted
opinions
PLATO AND ARISTOTLE

14. Plato thought that we
have innate ideas of
geometry and
justice because any
person can correctly
think about them
PLATO AND ARISTOTLE
PLATO

15. Our senses perceive
imperfect objects
and unjust actions
that only wake up a
sleeping memory of
ideas
PLATO AND ARISTOTLE
PLATO

16. Aristotle did not accept
innate ideas: all
knowledge comes
from the senses. We
make ideas through
abstraction
PLATO AND ARISTOTLE
ARISTOTLE

17. Plato is the first
rationalist
philosopher, and
Aristotle the first
empiricist
PLATO AND ARISTOTLE

18. THE FOUNDATION OF
KNOWLEDGE
1. Sense perception and rational knowledge
2. Plato and Aristotle
3. Galileo
4. Rationalism and Empiricism
5. The foundation of knowledge

19. Galileo lived more than
20 centuries after
Plato and Aristotle,
in 17th century Italy.
He renovated
science deeply
GALILEO

20. He created the modern
scientific method, and
introduced the use of
mathematical
calculations, observation
instruments and
experimentation in
laboratory
GALILEO

21. Rationalist elements
(mathematics, method)
and empiricist
(observation,
experimentation) live
harmoniously together in
his Physics
GALILEO

22. THE FOUNDATION OF
KNOWLEDGE
1. Sense perception and rational knowledge
2. Plato and Aristotle
3. Galileo
4. Rationalism and Empiricism
5. The foundation of knowledge

23. When philosophers and
scientists after
Galileo wanted to
explain his science,
they basically took
two attitudes:
RATIONALISM
AND EMPIRICISM

24. Some thought that the
new science’s
progress was due to
method and
mathematics: the
rationalist elements
RATIONALISM
AND EMPIRICISM

25. And others thought that
it was due to
experimentation and
observation
instruments: the
empiricist elements
RATIONALISM
AND EMPIRICISM

26. Descartes was the
starter of the
rationalist school of
Modern Age. He
was contemporary
with Galileo (17th
century)
RATIONALISM
AND EMPIRICISM
RATIONALISM

27. Descartes thought that
reason could obtain
by itself the most
certain scientific
knowledge
deducting it from
evident truths
RATIONALISM
AND EMPIRICISM
RATIONALISM

28. Example: in his Discourse
on the Method he
proves that the soul,
the world and God
exist using only the
sentence I think,
therefore I am.
RATIONALISM
AND EMPIRICISM
RATIONALISM

29. Descartes, like many
rationalists, was a
great
mathematician. His
Physics, on the
other hand, contain
some errors
RATIONALISM
AND EMPIRICISM
RATIONALISM

30. This happened also to
other rationalists:
Spinoza, Leibniz...
RATIONALISM
AND EMPIRICISM
RATIONALISM

31. Locke, who lived in the
late 16 hundreds,
was the most
significant
philosopher of the
modern empiricist
school
RATIONALISM
AND EMPIRICISM
EMPIRICISM

32. Locke phrased the
principles of
empiricism: Sense
perception is the
origin and the limit
of all knowledge
RATIONALISM
AND EMPIRICISM
EMPIRICISM

33. F. Bacon was the first
empiricist author,
and lived before
Locke. Later, Hume
took empiricism to
the edge, leading it
into skepticism
RATIONALISM
AND EMPIRICISM
EMPIRICISM

34. Rationalism and
empiricism only
explained partially
Galileo’s Physics.
Kant was the first
one to give a full
explanation
RATIONALISM
AND EMPIRICISM

35. Kant’s theory of
knowledge, one of
the most complex in
the History of
Philosophy, exceeds
the contents of this
course
RATIONALISM
AND EMPIRICISM

36. THE FOUNDATION OF
KNOWLEDGE
1. Sensible and rational knwledge
2. Plato and Aristotle
3. Galileo
4. Rationalism and Empiricism
5. The foundation of knowledge

37. THE FOUNDATION OF
KNOWLEDGE
The problem of the foundation of knowledge
may be phrased this way:
How should sense perception and rational
knowledge be related, so we could
advance in knowledge avoiding error?

38. There are two philosophical schools that
answer the question:
Rationalism and empiricism
THE FOUNDATION OF
KNOWLEDGE

39. They believe that the senses deceive us and
only reasons provides reliable knowledge
They value method and mathematics
They usually understand truth as coherence
Plato was a precursor rationalist school of the
modern age, to which Descartes, Spinoza
e Leibniz belong
RATIONALISM
THE FOUNDATION OF
KNOWLEDGE

40. They believe that all knowledge comes from the
senses. Reason makes ideas from what we
perceive
They value observation and experimentation
They usually understand truth as correspondence
Aristotle was a precursor of modern empiricism, F.
Bacon, Locke and Hume belong to it
EMPIRICISM
THE FOUNDATION OF
KNOWLEDGE

41. Modern rationalists understand truth as
coherence and empiricists as
correspondence
Plato and Aristotle, who lived before Galileo,
don’t doubt knowledge as much as
moderns do: they understand truth, more
intuitively, as correspondence
PLATO AND ARISTOTLE
THE FOUNDATION OF
KNOWLEDGE

42. Iin order to solve the problem of the
foundation of knowledge we need to think
what is the role of the rationalist (method,
mathematics) and empiricist (observación,
experimentación) elements
What is your opinion?
THE FOUNDATION OF
KNOWLEDGE

43. Could we have the idea of a horse if we had never
seen one?
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION
Almost everybody agrees that science begins by observing nature. Only authors that
found their philosophy in religious concepts, such as Plato, accept that we have innate
knowledge of nature.
THE FOUNDATION OF
KNOWLEDGE

44. What is the perimeter of a regular polygon of 497
sides if each side is 1 m long? Do we need to
observe such a polygon to find an anser?
Mathematics and Logic are called formal sciences, because their object of study does not
depend on what exists in nature: we can reason about objects that never existed and trust
that, if one day such one existed, it must necessarily be as Mathematics calculate.
The rest of sciences are called empirical, because they depend on it.
THE FOUNDATION OF
KNOWLEDGE
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION

45. Could we find the physical laws of movement by just
observing how things move in nature?
Empírical sciences often need to make experiments, because mere observations are
impredictible and imprecise. In experimentation we provoke the fact in a laboratory, where
everything is ready to make precise measurements. The experiment must also be repeated
in other places so that other laboratories may confirm the results.
THE FOUNDATION OF
KNOWLEDGE
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION

46. What happens if I go into a lab and start to
attentively watch what occurs there?
NOTHING. Nothing happens in a lab if it is not intently provoked.
This means that mere observation does not work in a lab. Scientist must be ahead of their
experiments, foresee the possible results and put forward a hypothesis about what is going
to happen when they provoke the event. These anticipation and hypotheses are the work of
reason that senses cannot do on their own.
THE FOUNDATION OF
KNOWLEDGE
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION

47. Can I perform an experiment to find out the
perimeter of a regular polygon of 497 sides,
each 1 m. long?
Yes, but it’s utterly useless: if the result wasn’t 497 m. I would conclude that the
experiment wasn’t correctly done. Formal sciences do not depend on experimentation,
because they do not depend on observación in the first place.
Here is a situation where reason has the upper hand on what senses observe.
THE FOUNDATION OF
KNOWLEDGE
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION

48. How can I detect an error in a theory?
Errors in theories are usually discovered through observation and experimentation: Doing
the math according to a theory we reach the conclusion that what should happen is this...
and then we observe that other thing happens. Thus new planets were discovered,
unknown chemical qualities of elements...
We see here a case where senses must control what reason proves.
THE FOUNDATION OF
KNOWLEDGE
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION

49. Do I need to make an experiment to find out if killing
is bad?
Empirical sciences are usually divided into natural sciences, such as Physics and
Chemistry, and social or human sciences, such as History and Economics. Human sciences
have very strict limits on experimentation since it has to be done on human beings.
Here, reason is alone in the investigation, though we must always consider that senses
show us what is pleasant or unpleasant for us and for others.
THE FOUNDATION OF
KNOWLEDGE
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION

50. Is Psychology a social or natural science?
SOME QUESTIONS
TO HELP YOU BUILD YOUR OPINION
Scientists themselves do not agree on this matter. Psychology must be able to cure a
suffering person, as Medicine does, but this only happens if this person tells what happens
to them and takes part in the solution. Pills and aggressive treatments suppress some
symptoms but do not solve out problems. But, on the other hand, an ill person's
interpretation is barely reliable. What is your opinion?
THE FOUNDATION OF
KNOWLEDGE