phil 27

study guide

“Kant’s philosophical goal was to use logical analysis to understand reason itself. Before we go about analyzing our world, Kant argued, we must understand the mental tools we will be using. In the Critique of Pure Reason Kant set about developing a comprehensive picture of how our mind–our “reason”– receives and processes information.” (Sparknotes)

Our understanding of the world very much depends on how our minds work. Brief example would be how nothing in our perception of the world (sensory data) tells nothing about the causation. Yet, when we see a baseball breaking a window, we automatically think that the baseball caused the window to break. This is called “Copernican Revolution” in philosophy

“In the Critique of Practical Reason and the Grounding for the Metaphysics of Morals, Kant applies this same technique–using reason to analyze itself–to determine what moral choices we should make.” (Sparknotes) Kant developed his moral theory on the basis of fundamental principles of reason alone.

Helpful definition: Metaphysics is the study of pure concepts as they relate to moral or physical experience. This comes after studying physics so metaphysics literally mean ‘things after physics’ implying that metaphysics is the study of things or concepts that transcend physical or natural realm.

The goal of the Grounding for the Metaphysics of Morals is to develop a clearer understanding of moral principles which can be applied to any situation.

What Moral Law Should We Follow?

  • Maxim: Subjective principle of volition
    • The goal or ends or objectives we as rational beings set up
    • “I choose to do A to bring about B”
    • When _____,  Do  ___A___ for the sake of  ___B___
  • Categorical Imperative
    • Definition
      • command that applies regardless of what ends have been adopted
    • Three formulations
      • Universal Law Formulation
        • Act only according to that maxim whereby you can at the same time will that it should become a universal law
        • Test of Universal Law Formulation
          • Formulate Maxim
          • Universalize Maxim
          • Contradiction in conception
            • This is a violation of perfect duty
            • Examples
              • Lying
              • Committing a suicide
          • Contradiction in will
            • This is a violation of imperfect duty
            • Examples
              • Not being charitable
              • Being lazy in self-improvement
          • The Maxim is universlizable if it involves neither contradiction in conception and contradiction in will
      • Humanity Formulation
        • Never act in such a way that you treat Humanity as a mere means and not also as an end into itself
  • Hypothetical Imperative 
    • Definition
      • command that applies given that you have adopted certain ends
    • Examples: I have to study hard given that I want to achieve A in the class
    • Utilitarianism is all about hypothetical imperatives
    • This is about bringing about a certain state of affairs or achieving certain objective

Why Should We Follow Such Moral Law?

  • Because we want freedom!!
  • Freedom is the ability to give your own law to your will
    • Autonomy is when we follow the categorical imperative and choose maxims that could be universal laws
      • We use reason to determine our own law for ourselves, in other word, we are free
    • Heteronomy is when we follow the demands of some need, desire, and circumstances
      • Our will is determined by something outside of ourselves, in other word, we not acting freely


Helpful summary:




Phil 10 – Ch. 3

In chapter 3, we continue to look for ways to determine the validity of the argument. Before moving on let me remind myself again on the role of logic: “Logic does NOT answer the question of are the premises of the argument true? All logic can say is whether the inference of the conclusion from the premise is valid. Logic can never tell us if our arguments are sound.” And let me remind that whether the premise is true or not can be assumed by observation in case of science. In mathematics, however, which is called the logic fully developed, we just assume axioms and postulates to go on to prove theorem. And also remember that you cannot prove anything without accepting something.

I can only write down summary in words. For clarification, please refer to diagrams and illustrations on the textbook! (It’s much more helpful)

  • Proof method in general
    • A way of reaching conclusion by adding lines of premises according to rules of inference
    • You keep adding new lines until you reach a conclusion statement
    • You must add new lines according to rules of inference
    • Proof is finished when you reach a conclusion
  • Rules of inference
    • Modus Ponens (MP, “method for providing”)
      • If there is a line of conditional and an another line of antecedent of that conditional, you can add the consequent of the conditional
    • Two Important remarks before moving on
      •  Justification
        • You need to write down what rules you apply to what number of premises next to the new line you add
        • In other word, you have to justify the new line you add!
      • Rules of inference apply to the whole line (not component of a line)
    • Modus Tollens (MT, “method for removing”)
    • Disjunctive Syllogism
    • Simplification
    • Conjunction
    • Disjunction Introduction (DI)

Phil 10 study note-Ch.2

Chapter 2 of formal sentential logic

  • The purpose of truth function and table
    • To find the validity of the argument easier
  • Limitation
    • 1) How do we represent other complicated statements
    • 2) What if there is no row where all premises are true?
  • Answer to limitation 1)
    • Enlarge the truth table
      • (This is easy)
    • After adding the truth columns find the row where all premises are true
    • If there is any row where all premises are true, and conclusion is false, then argument is invalid
  • Answer to limitation 2)
    • Terminology to answer limitation 2)
      • Types of statements (concerns single statement)
        • tautologies
          • statement that is always true
          • applies only to compound statement
          • nothing follows from tautology
            • if you tell your roommate “I took a shower or I didn’t”, you actually informed him nothing
        • contradictions
          • statement that is always false
          • applies only to compound statement
          • everything follows from contradiction
        • contingencies
          • atomic statements are always contingent
      • Relations between statements (concerns more than 2 statements)
        • equivalency
          • truth columns of two statements are exactly the same
        • consistency
          • there exists one row where the statements are true
          • limitation 2) is when the premises are not consistent
            • how can we tell if the argument is valid?
        • implication
          • An argument is valid iff the premises jointly imply the conclusion
            • which means there is no counter-example row
    • Answer to limitation 2)
      • Argument is valid where the premises are inconsistent
      • So before, we had to find a row where premises are all true and conclusion is also true. However, in the case where there is no such row, we can now tell the argument valid if there is no counter-example row.
      • Counter-example row
        • row where premises are all true and conclusion is false
        • when there is no counter-example row the argument is valid even if there is no true where both all premises are true and conclusion is true.
        • Basically, all you need to do to figure out validity of argument by the truth table is to find a counter-example row
          • if you find one, then the argument is invalid
          • if you don’t, then the argument is valid
          • esayyyyyyyyyy
      • The conclusion is that the test for joint implication is same as the test for validity
        • if s1, s2 jointly imply s3, then s1, s2 are premises for conclusion s3 of the valid argument.

Meaning and truth

Whether the sentence is true of false depends on two things: what the sentence means and how things are in the extra-linguistic world. For example, the sentence “God exists” can be true when it means that God is there and when God really does exist. This intimate relationship between the truth and the meaning implies that a natural language is primarily informative.

Choosy mothers chose Jiff means
that choosy mothers chose Jiff.
Choosy mothers chose Jiff.

Choosy mothers chose Jiff is true.

We can learn about things about the world through language and through sentences we can learn things about sentences through the world.

This is very interesting as I start to really think about it. Is by means of language that I communicate with other people. What we try to mean, we mean by what we say. We can also communicate what we believe and affirm by how we live. But when it comes to semantics, it is through language that we express our ideas and beliefs and information. Also, how is information stored in our mind? Through forms of language whether it’s verbal, formal, or whatever.

What does Jesus mean? The word “Jesus” refers to the historical figure that lived in 2000 years ago in Nazareth, Judea. It refers to Jesus as recorded in gospel who lived, suffered, died and resurrected for the catholic church. When I say “I believe in Jesus Christ as my Lord and Savior,” it does not mean I believe in certain kind of ideas or concepts or emotions called Jesus. Rather, it means I place my trust in this historical figure who exists as God-man who accomplished salvation for all the elects of God. When I say I believe in him, that means I place my trust in this really-existing person who is seated at the right hand of God right now and intercedes for his church.

What does the gospel mean? First of all, it is good news. What is the good news about? What does it refer to? What is the content of message of it that it tries to communicate? It is what Jesus has done in space and time. It is a story of God who promises eternal life to everyone who places their trust in Jesus Christ.

Logically valid deductive argument is defined like this. If all the premises were true, then the conclusion has to be true. It is important to note here that it doesn’t matter whether the premises are actually true or false. With ridiculously false premises, deductive argument can still be perfectly valid. 

Aha! Even perfectly valid deductive arguments do not guarantee the truth of the conclusion. It only guarantees the truth of conclusion only if the premises were true. The conclusion derived by premises must be true if and only if the argument is both valid and sound.

When Greek philosophers reason and argue, their arguments can be perfectly valid. They have good tools of reasoning. In many cases where their premises are also true, their conclusions are true too. With this tool of logic, philosophers could figure out many truths concerning natural world.

However, when it comes to spiritual world and theology, special revelation is necessay for us to know who God is. If God does not reveal himself, our premises concerning God cannot be true. 

  • Statement Operator
    • Conjunction
      • P•Q
      • conjunct and conjunction
      • logical meaning of the operator is that both conjuncts are true
        • “however, but” are also conjunction operators
      • compound subject and compound predicate
        • can express conjunction
    • Negation
      • the negated statement
    • Disjunction
    • Conditional

That means even if but and however convey different psychological import, nevertheless they have the same logical meaning and it is that both conjuncts are true.


When it comes to morals, the end at which all actions aim determine the character of all actions.

And every school of thought admits that the influence of actions on happiness is a very significant and even predominant consideration in many of the details of morals.

Men lose their high aspirations as they lose their intellectual tastes, because they don’t have time or opportunity for indulging them.

I wholeheartedly agree with this statement. As I grow in age and wisdom and reasoning, I start to appreciate intellectual activities much more than before. I have started to behold the beauty of good arguments based on good reasoning and factual premises. Study was something that I was forced to do by my parents; however, it is something I enjoy very much nowadays. I thought myself that I want to spend my life researching and engaging with intellectually challenging materials. I wish I had gone through better education system such as classical education system.

Nicomachean Ethics summary

Every human action is done toward an end. All human activities have purpose. And there exists the ultimate end at which all human actions are directed. This ultimate end is ‘happiness’ which is translated from Greek word ‘Eudaimonia.’ This word can be also translated as ‘human flourishing’ or ‘man fully alive.’

Okay, let’s say we all agree with this assumption that all human activities are done for the ultimate end, which is happiness. However, how can we define this ‘Eudaimonia’, happiness? What is it exactly? What is the nature of it?

Before moving further, Aristotle assumes that human happiness consists in fulfilling the natural function of a human being. For example, knife fulfills its function when it cuts well, and when the knife cuts well, we can say knife is in well-being. Then, what is the function of man?

Aristotle first defines function proper to man. What is uniquely human activity? What is uniquely human function? Aristotle says it is our ability to reason, think intelligently. All other activities of human being such as digestion and respiration seem to be shared by animals. However, our reason and intellect is what distinguishes us from animals.

Therefore, man can attain happiness when he is fully engaged in this intellectual activity of reasoning and thinking. More practically, when man directs his action according to this reason and behaves deliberately and willfully, he is fulfilling his function as a human being and this will lead to his happiness. And this intellectual activity is expressed by ethical virtues, which are habit disposed toward right action according to right reasoning.

According to Aristotle, therefore, ethics is entirely by-product of reasoning.

For us, Christians, we know that the function of a human being is to glorify God and enjoy Him forever. We are created by God to glorify Him. Therefore, when we glorify God and live in fellowship with Him, we can truly be happy. When we are truly holy, that is, when we live in conformity to God’s law, we fulfill our function as a human being, and happiness follows (or we become men fully alive).

Aristotle was indeed bestowed the common grace of the Holy Spirit and much natural light can be found in his argument. His philosophical works have been a great help to preserving human race and restricting sinful nature. How can we not say that this is God’s providential grace.