Meditations Three and Four
On the basis of the argument in Meditations One and Two Descartes claims that there are
ideas in the mind that enable me to know minds and certain features of bodies (if they
o e.g. Innate idea of extension enables me to identify the wax even though it has
I perceive with the mind using clear and distinct ideas.
o Perceiving = Judging, not sensing or seeing
Things are perceived only insofar as they are understood, and what can be more clearly
understood than my own mind?
But, my mind is not a body in the physical sense.
I can doubt the existence of physical bodies but that doubt affirms the existence of the
“I”, my mind (reason).
What sorts of ideas count as clear and distinct?
o Sensible things: the only thing we perceive clearly is that "ideas, or thoughts, of
such things occurred before my mind".
What we do not perceive clearly is "that there were things outside me which were the
sources of my ideas and which resembled them in all respects."
o Clear and distinct ideas: intellectual ideas that are self-evident or analyzable into
their component ideas (e.g. the idea of a triangle = 3 angles summing 180
Could clear and distinct ideas be false? Descartes hasn‟t shown they can‟t be.
This could happen if God was a deceiver so he must show that God exists and that he is
not a deceiver.
First, we need to answer the following question(s):
o Under what conditions am I justified in taking any of my ideas as true
representations of things existing outside of me?
o Under what conditions am I justified in inferring from the presence of a certain
idea to the existence of the object represented by that idea? This latter question is what Descartes attempts to answer in his proof for the existence of
We often assume this to be the case but on reflection we find it to be false. Habit directs
us to do this.
How did we arrive at this notion of externality?
Need some way of investigating the cause of our ideas.
Classification of thoughts:
IDEAS: These are like images of things – Man, God, Wax etc.
We affirm, deny, etc. – I grasp something that is the subject of my thought.
Ideas involve two types of reality:
o Objective reality: the reality a thing has in the mind as the object of an idea (the
thing represented in the idea).How real is something
o Formal reality: Real or intrinsic reality.
o All ideas (considered just as ideas) have exactly the same formal reality, because
they are all modes of thought.
Reality is based on the amount of things a substance is dependent on – dependent on less,
o Infinite substance (God)
o Finite substances
Only ideas have objective reality
Ideas are modes/properties in terms of formal reality
Eg. A substance has the formal reality of a finite substance, therefore, the idea of that
substance has the objective reality of a finite substance and the formal reality of a
Minds are substances that support the existence of ideas; because ideas depend for their
existence on a mind, the latter has more "reality" than the former.
Minds have finite formal reality while God as infinite formal reality (Scholasticism). Objective reality of an idea is the reality that the object of the idea is depicted as having.
Ideas can have different objective reality based on what they represent. (stone vs.
Ideas representing substances have more objective reality than ideas representing
Accidents – secondary qualities
The idea of a finite substance has less objective reality than the idea of an infinite
substance (God), because the former idea represents a less perfect being than the latter.
Because all ideas have causes (even innate ideas), what is the relation between the reality
of the cause and the idea?
There needs to be as much reality in the cause as in the effect (this is true for both ideas
Something cannot bring about something with more power than itself
Descartes claims that this is known “by the natural light”. In other words, it is a self-
If there is an idea with a certain degree of objective reality, it must be caused by
something that has at least the same degree of formal reality.
Where else could the effect get its reality if not from its cause?
What is more perfect and contains more reality cannot proceed from what is less perfect.
So, how did I get the idea of God (i.e. what is its cause) if I am just a finite being with a
We could only have the ideas we do--ideas which possess a certain degree of objective
reality in virtue of the things they represent--if those ideas were produced by a cause that
has at least as much formal reality.
Causes – Contain Formal or Intrinsic reality.
Once he shows we possess the idea of God he then uses this to argue for the existence of
God by showing that only God could cause the idea. Cosmological Arguments are causal arguments. In this case it is from the existence of an
idea to the cause of the idea.
o The main argument of Meditation Three is that while I could have composed my
ideas of physical objects without these existing (there is an argument to show that
this premise is true.) only God can be