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Summary IB Philosophy Core Theme (Human Nature) Revision Notes
What is Human Nature?
Human Nature, or essentialism, is a branch of metaphysics that questions whether a universal
teleology exists: what universal characteristics all people possess naturally. This is a significant
branch of philosophy as it informs us how we ought to live our lives, and what ends we should
attempt to achieve throughout our life.
Plato: Theory of the Forms;
Plato’s Theory:
“It is not possible to step into the same river twice” - Heraclitus.
Plato questioned how one can hold knowledge of anything when the world was in a constant state of
flux. This is because Plato saw knowledge as permanent and unchanging. He concluded that
knowledge is possible because there exists a realm of Forms - a conceptual realm, mirroring the
empirical world but independent of it and the human mind, in which everything exists in its most
perfect state. Example: there is a Form of a circle that all circles resemble but do not ever completely
embody.
This is an epistemic metaphysical proposition that claims there are two levels of reality.
Plato’s Argument:
Plato’s argues we have knowledge of the Forms through our souls, which consists of three parts:
1. Spirit; the part of ourselves that is emotive.
2. Hedonistic desires; the part of ourselves that yearns for temporal desires.
3. Reason; the part of ourselves that governs the spirit and hedonistic desires - aiming to create a
harmonious balance.
Note: Plato uses the chariot analogy to explain this.
Plato places special importance upon reason as he believes it controls spirit and hedonistic desires.
Only when reason does this can we discover knowledge of the Forms. Notwithstanding, this control
must be habitual. Just like how a good violinist develops better skills only with continual practice, so
too must one continually employ reason.
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Therefore, Plato asserts that the soul is the link between man and the realm of the Forms. He explains
in the Phaedo (427 - 348bce), where he argues the soul had complete knowledge of the Forms prior to
birth. However, upon entering the material world it is lost, and we must undergo anamnesis - the
doctrine of learning as recollection - to familiarise ourselves with the Forms once more.
Evaluation: Weaknesses;
1. Plato does not clarify the scope of the forms. Originally, in Book Five of the Republic, Plato
asserts “there are forms for qualities that have opposites”. However, later, in Book Ten, he
declares there is a form for “each set of things we apply the same name”. This is problematic
as all concepts may have forms. Originally, forms had opposites and, hence, could be
identified by the extent to which they differed from their opposite. However, now, ideas, like
justice, have forms, yet it is unclear as to how one could determine what this would be
without a point of reference. Is justice a political system or is it adherence to a particular
normative theory?
2. The realm of the forms is separate from the material. Consequently, it encounters many
similar problems of dualism in that it cannot explain the interaction. Plato’s explanation is not
only unsubstantiated but, given the scientific evidence to suggest the legitimacy of
materialism, also unlikely. Ockham’s Razor demonstrates that in such cases where a theory is
both unlikely and unclear it’s likely also untrue.
3. The problem of silly Forms. Since every material thing is a reflection of its immaterial Form,
even things such as seaweed would possess Forms. This is strange considering many such
things can not be measured on a scale of goodness. How could there be a Form of seaweed?
This would require one to identify the essence of seaweed, which I affirm would be an act
arbitrary preferencing. Hence, the theory of the Forms is often a poor ontological description.
4. The problem of misusing language. Many philosophers, such as Ludwig Wittgenstein, have
demonstrated that the Forms encounter linguistic difficulties. Every attempt to define a Form
will overlook some aspect of reality. For example, even if the Form of a game is as open as a
competitive practice needing two teams, games like solitaire are still excluded. Rather than
believing in an objective immaterial world, it seems far more reasonable to accept that it is the
person who applies the term game, and the common understanding of what a game is, that
determines what constitutes a game.
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Aristotle: Virtue Theory;
Aristotle’s Theory: “Reason is the true self of every person”
Aristotle constructs a teleological narrative that, similar to Plato, places importance upon the habitual
exercise of reason.
Aristotle believed everything had a telos, and one can determine a thing’s telos by examining what it
did best - its proper function. Aristotle believes man is zoon politikon - a political animal. Thus, our
proper function is habitually using reason within political communities.
Doing this allows people to achieve eudaimonia - human flourishing. Note, this isn’t hedonistic
instant gratification, but the happiness derived from living a good life.
Aristotle’s metaphysical proposition heavily influenced his ethical doctrine - virtue ethics.
{See Aristotelian Virtue Ethics for further elaboration and clarification}
Aquinas: Natural Law;
Aquinas’ Theory:
Thomas Aquinas was a biblical Christian theologian. He wrote in a time where not many people could
read the bible as it was in Latin. Therefore, Aquinas’ theory attempts to demonstrate we possess an
underlying human nature that is discoverable without reference to biblical scriptures.
Aquinas theorized that humans must possess the ability to know God’s will.
He believed that the characteristic that enables this is reason, as it is exclusive to humans.
“In living the life of reason we are to actualize the modes of existence which move us closer to our
final end, God”
Aquinas concluded that using reason to reflect on our natural inclinations we become aware of our
essence. This process is Synderesis.
Aristotle called these self-evident natural inclinations Primary Precepts. He believes there are four:
1. Human beings attempt to sustain their existence - hence “conserve and protect health”
2. Humans naturally seek to propagate - hence, “marry and multiply”
3. Human beings are rational creatures - hence, “we should seek knowledge”
4. Human beings are social creatures who live as members of communities - hence, “live
peacefully in a civic community”
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In the Summa Theologiae Aquinas outlines one can apply knowledge of the Primary Principles to
derive Secondary Principles. Aquinas called this process Consientia. Furthermore, he applied them in
the form of a Practical Syllogism.
Note: Although Primary Precepts are self-evident, their application to derive secondary principles is
fallible. Thus, secondary precepts are subject to criticism. For example, marry and multiply may not
necessitate one practice monogamy.
Evaluation: Strengths;
1. Aquinas’ theory provides a basis for objective normativity. This is useful for establishing
human rights and fighting the charge of relativism.
Evaluation: Weaknesses:
1. The Darwinian Challenge. Refer to the section on virtue ethics. Reason is not a distinctly
human trait, it has evolved.
2. The is-ought problem. The scottish philosopher David Hume demonstrates that any claim of
normativity is unsubstantiated because it is impossible to use anthropological observations to
determine a normative claim. Hence, the claim that the human propensity for reason leads us
towards the aforementioned precepts does not signify that they are normatively sound.
3. The theory rests on the jeodeo-christian teleological narrative. If one offers a different account
of human nature, such as Thomas Hobbes in Leviathan when claiming human beings are
naturally selfish, or, as the existentialist does, reject the idea of human nature, then this theory
cannot stand.
Existentialism:
The Existentialist Claim:
Existentialism argues that there is no universal telos. Rather, it argues the human condition is the
freedom to create our own nature.
Sartre’s Existentialism is a Humanism:
Jean-Paul Sartre, in Existentialism is a Humanism, argues that existence precedes essence. Humans
are not defined by rationality or materiality, they are a project that possesses a subjective life. Sartre’s
aim is to assert the value of human life in the absence of a God and persuade his critics that
existentialism is not vicious or selfish. Note, Sartre uses a phenomenological method. He is concerned
with studying the experiences of the conscious mind as this, he believes, is all one can really know.