Discipline of Philosophy
Is non-empirical and deals with reflective questions.
Method of Philosophy
That of self-reflection and critical thinking.

What’s the point? There are several answers to that.

  1. Philosophy needs no point. Understanding for its own sake is sufficient.
  2. Our philosophical outlook affects our actions. Bad philosophy yields poor decisions and beliefs.
  3. Reflection allows us to re-evaluate our beliefs.


Descartes’ central task was to reconcile science with the human spirit and God. This he did in his Meditations.

In his First Meditation, Descartes introduces the method of doubt to protect himself against the Evil Demon (the Cartesian version of the brain in a vat).

In the Second Meditation, he establishes certainty in himself and introduces the famous cogito ergo sum.

The argument for Cartesian Dualism can be shown invalid (see the masked man fallacy). Lichtenberg even rejects Descartes’ use of the word “I”. Descartes is the founder of rationalism.

Rational Foundationalism
Unaided, a priori reason is how we achieve knowledge. It rejects knowledge obtained by experience of the world.
Trademark Argument
Demonstrates the existence of God through the idea of “perfection”.

This argument is rejected by Arnauld on the basis of the Cartesian circle. Descartes’ method of saving us from universal doubt has failed.

Natural Foundationalism
Hume claims we stand on obvious but not demon-proof foundations to self-correct ourselves.

Empiricists argue that knowledge is acquired by sense, not unaided reason.

While “every argument needs premises, there is nothing that is the premise of every argument”—like a network.
There is no knowledge.

These four are the central theses of Epistemology, the study of knowledge.

The Omphalos hypothesis and Russell’s five minute hypothesis are examples of possible and frightening possibilities. This leaves certain knowledge and absolute confidence in the true nature of reality a major problem.


Substance Dualism
Two kinds of substances, mental and physical within each human.
Property Dualism
Two kinds of properties, but of the same substance.

There are some problems with Substance Dualism.

  1. Zombie
  2. Mutant Possibility

Each opens an epistemological problem regarding knowing about other minds.

Argument from analogy of other minds is a weak solution as Wittgenstein points out.

Physical events don’t cause mental ones, but God does (Malebrache).

Locke takes this approach whereby God does a few things.

  1. Fixes physical law.
  2. Decides psycho-physical relations (implies possibly independent action).

Leibniz rejects this and claims only the first. If God wants to change physical-mental interaction he must change the physical laws themselves (this rejection of arbitrariness is the principle of sufficient reason).

Pain can be analyzed in a number of ways.

Logical Behaviorism
The sensations are the pain, no consciousness is needed.
Similar to the above but allows for more physical relationships.

Qualia are the raw feelings, not any behavior (e.g. the “unpleasantness” of pain).

Psycho-Physical Identity Theory
A posteriori we can associate similar physical states with mental ones (as we did with mean kinetic energy and temperature).

Along with zombies and mutants is the problem of your past-self. Is it the same as what it is now? This is Wittgenstein’s anti-private-language argument.

Reification is the mistake of regarding all nouns as “things” (e.g. thought).

Free will

Every action follows from previous causes.
Hard Determinist (Incompatibilism)
Determinism and free will are incompatible.

There are a number of challenges to free will.

  1. Introducing quantum-style non-determinism doesn’t help either given that randomness introduces no freedom (dilemma of determinism).
  2. Schopenhauer (in passage on water) and Wittgenstein (in passage on leaves) criticize the argument of freedom by consciousness.
  3. Dualism doesn’t help either just by introducing a mental component. One also has to deal with the issue that physical systems are closed.
  4. Epicurus claimed that spirit could cause atoms to swerve, but physics (i.e. conservation of momentum) tells us this isn’t true.
Determinism and free will are compatible.

By acting against certain actions we may be able to alter flexible “modules” in the brain. It is justified in this case but not in the case of someone drowning for example.

Interventionist (Libertarian)
Some ghost from outside controls. Contra-causal freedom.

In opposition to interventionalism, the compatibilist puts freedom within not outside nature. Compatibilism is still somewhat problematic. No blame can ever be given if we could not have done otherwise.

Spinoza advocates for integrating knowledge and understanding with freedom. One can revise compatabilism to suit this (which can handle things like the Twinkie defense). But human agency is still missing from the picture. Compatibilism objectifies—treats humans as patients. This is Strawson’s critique.

The problem of free-will occurs in reconciling the first-person and “objective”-scientific-third-person.

Lazy Sophism
Because the future is fixed precautions aren’t needed.

This argument is quite invalid as you don’t know your fate and therefore should take precaution in such case that it would matter.

Fatalism is a mindset in times of consolation, but we must adopt a different one in the heat of action. One may be appalled at the coldness of determinism, but the flexibility of human nature is reason to think otherwise.

The self

Intuitively (especially in religion) we think the “I” can exist outside our ordinary human experience (e.g. life after death). Can we pinpoint the self?

If we accept “I” as non-composite we may be compelled to argue for immortality. But this also implies existence before birth. Identifying the self through continuity as Locke does still leavs The Ship of Theseus as a problem.

Locke notes that if the self persists in physical change, why not the immaterial? Kant makes a similar point. Pure dualism cannot solve the problem of the self.

Locke’s self
“I” must be conscious of my previous self’s experience to be the same.

This rules out things like reincarnation, but also causes amnesia to interrupt identity.

Brave Officer Objection
Reid’s argument that Locke’s view of self violates transitivity.

Locke’s response is to reject the necessity that “same person” means “same human being”. He did this to justify the notion of responsibility (as in the court of law).

The violation of transitivity may not be a problem if we consider people as composite and not simple as Reid does.

No Ownership Theory (Bundle Theory)
The self is an aggregate of perceptions. Only content no container (Hume).

This is similar to Lichtenberg’s rejection of Descartes use of “I”.

The criticism of this doctrine would be that experiences are adjectival—they need some subject to act upon. Some minimal consciousness of “the self” is likely necessary for any potentially intelligent interpretation of the world. A perspective and awareness of “I” is a structural requirement of interpretation (Kant).

Suppose after a scrambling process you emerge as two people. Which is you? One could think of it as a splitting road (Lewis), but subjectively how does that make any sense?


Some perspectives on religion are non-metaphysical and speaking of truth and falsity is inappropriate (as it would be in a poem).

However, most commonly religions make metaphysical claims and these are the beliefs to analyze.

Terms can have a sense (i.e. intelligibility) but no reference. Adding that something exists by definition does no good as “existence is not a predicate”.

Anselm’s Ontological Argument
Reductio ad absurdum starting from atheistic premise. A priori existence of God from conceiving a higher being.

Anselm’s contemporary Gaunilo refutes this with the Perfect Island argument. Anselm’s argument is suspect, but philosophers have different reasons why that should be so. Aquinas rejects is outright.

Cosmological Argument
This argument suggests that necessity of God as a “first cause”.

Russell’s argument is that the argument’s conclusion contradicts its premise. The theologian would likely reply with the claim that God is “causa sui” self-causing unlike normal beings. Still, our infinite regress arbitrary stopping point is a cause of concern.

Argument by Design
An analogical a posteriori argument that sees the world as though it were engineered by a human-like mind.

This argument loses credibility against Darwin, but fine-tuning can be argued instead. Hume rebuts this argument by rejecting that we have sufficient experience to make an analogy. Why couldn’t the creator be a vegetable rather than an intelligent human?

Hume continues to argue against analogy by introducing the presence of enormous evil in the world. If we infer human intelligence from design, we can infer evil from the immorality present?

The modern refutation against this is objection to inquiry into God’s nature. The consequence is we have a totally incomprehensible and unknowable God (useless in Wittgenstein’s view).

Theodicy attempts to cope with the problem of evil in two ways.

  1. Evil exists to bring forth virtue (this is a stretch).
  2. The free will defense that evil comes from humans not God as a consequence of the goodness of free will.

There are numerous criticism of this defense.

  1. This contradicts the theologically standard interventionalism.
  2. Much evil is natural—non-human.
  3. Couldn’t God will to protect from abuse of free will?

We could potentially believe in God on the basis of miraculous occurrences. To refute this Hume introduces his eponymous razor. Few religious claims come even close to satisfying the necessary criterion for Hume (people lie). Hume is wonderfully Bayesian relying on the small base rate of miraculous occurrences and the greater likelihood of the alternative lying hypothesis.

Some claim religion’s correctness from popularity, but the mutual exclusion of religions necessitates most people will be wrong anyway.

Pascal’s Wager
Belief in God has immense utility and therefore we should believe.

In game theoretic terms belief in God is a dominant strategy.

The wager can be demolished by presuming a deity which gives negative utility (i.e. Hell) to believers.

Religion may not have great logical arguments, but it’s positive or at least inert. Let it be.

This answer doesn’t satisfy philosophers who care about truth, but fundamentalism is hardly inert anyway.


The basics of argument are a premise which derives a conclusion. Rejection comes in the forms of rejecting premises or the line of reasoning.

Aristotle began classifying and studying the structure of arguments. The discipline of logic cares about structure not content. It studies truth-functions (Boolean operators). Frege introduces predicates and quantifiers to better differentiate propositions.

Language can have both a truth-condition and implicature. Pragmatics deals with implicature while semantics deals with structure. Formal logic is neither coercive nor linear.

Problem of Induction
How can we justly infer from our limited experience to the future (Hume)?

We rely upon the uniformity of nature without possible justification.

Posterior probability (Bayesian) relies of base rates and the likelihood ratio. From a Bayesian analysis the uniformity still has no real justification.

Models don’t give true understanding—mechanisms do though. Hume rejects that thorough understanding is actually possible and that a priori reasoning is severely limited.

Kuhn continues in this vain suggesting paradigms are necessary to underlie the whole of our current truth. This doesn’t mean all paradigms are equal.

The world

Galileo introduces a distinction between primary qualities (of objects themselves) and secondary qualities (those which rely on human experience).

Descartes accounts for the deception given by the sensor as a necessity for survival (and not God’s fault). There is no reason the sense must report accurately if this goes against natural selection (in modern parlance).

He also offers dualism in the world as manifest image—our ordinary sensation and scientific image as objective reality. This also introduces the possibility of the relativity of senses.

One may object that one mind may miss vital information, but evolution’s assurance of well-functioning lives resolves this.

Some beings may not have equal adaptations in which case we take the sensory dimensions independently.

The argument for mind-dependent senses is secondary quality idealism (Locke). Berkeley criticizes Locke’s view as circular.

Faraday rids of things in themselves as all can be experiences by their power in the world. This too falls to the Humean critique. Forces are understood in terms of objects. This is circular.

Kant suggests this is as far as we can go being that the sense operate only on forces not the noumenal.

Another law of nature cannot be used to justify the uniformity of nature because once again we enter circularity. Kant disagrees with Locke’s transcendental realism and agrees with Berkeley. He develops transcendental idealism which changes the perspective.

Berkeley understands that one cannot isolate an experience from a perspective. Moore attempts aesthetic realism, but Berkeley’s argument refutes this.

There are three central arguments regarding the nature of reality:

What to do?

Psychological Egoism
All actions are ultimately selfishly motivate.

Blackburn criticism this view. Treating concerns as objects that can be solved inappropriately is wrong sometimes, especially when it is central to our identity. There are two ways to talk about concern.

Describe why a situation is moving.
Describe what is not moving them.

Some concerns we only expect or care of ourselves but others we also expect of others. It is difficult to imagine a society without this as it would be one without ethics, but the specific ideals are highly individualized and context-sensitive.

Ethical statements are propositions.
Ethical statements are not propositions.

Cognitivists want to ground ethics on truth. Blackburn sympathizes with the non-cognitivsts thinking that we are first motivated by good will and then subsequently develop normative propositions. To clarify our actions.

Therapy may not help if it objectifies concern and alienates people.

How does one treat others as ends? Not through deception or manipulation but by looking from the other’s point of view.

Any system of ethics has to be consistent in order to be put into practice. This can be difficult if different principles come into conflict.

We can resolve these boundary disputes in numerous ways.

  1. History
  2. Imagination
  3. Reflection

But relativism is not absolute—some ethical perspectives work better than others (even if some work equally well but differently).