Philosophy of Science Part 1 PDF

Philo 1: Philosophy of Science Hospers: Scientific Knowledge What is science? I. Introduction to the Philosophy of Science In observing the world, we notice regularities ○ The sun rises in the east ○ Iron rusts, but not gold ○ Chickens lay eggs, but dogs don’t...

Philo 1: Philosophy of Science Hospers: Scientific Knowledge What is science? I. Introduction to the Philosophy of Science In observing the world, we notice regularities ○ The sun rises in the east ○ Iron rusts, but not gold ○ Chickens lay eggs, but dogs don’t We notice these regularities and attempt to chart them. I. Introduction to the Philosophy of Science In contrast, we could also see irregularities ○ Some trees yield fruit, some not ○ Some seasons are rainy, some dry ○ Some dogs are friendly, some hostile But, irregularities make it difficult to make sense of the world I. Introduction to the Philosophy of Science In order for past experiences to guide us to the future, we need regularities. But generally, regularities are not invariable ○ You keep your son away a friend because that friend has a cold Your son gets a cold anyways ○ You let your son play with the friend with a cold Your son doesn’t get a cold I. Introduction to the Philosophy of Science What we desire are genuine invariants in nature ○ We look for conditions/regularities under which a certain type of event occurs without exception ○ The scientific enterprise could be described as the one searching for these things I. Introduction to the Philosophy of Science But science is very difficult. Sometimes we seem to have found genuine invariants but are actually not ○ “Water boils at 100 C” It seems invariant possibly in where we are right now. But go to mountaintops and it will change Further observations would lead us to believe that boiling point depends on pressure. Not temperature, time of day, nor moisture I. Introduction to the Philosophy of Science The entire reason we try to find these regularities is because we have a goal We are interested in predicting future events. Prediction allows us to act in accordance with the prediction ○ “If we see the sun low in the west, we can predict that the sky will soon be dark and that we won’t be able to conduct activities that require more light.” Science is the systematic search for uniformities in the way things behave ○ These are called laws of nature Laws of Nature I. What is a law of nature? Laws in Nature vs Laws in Legislation Legislation ○ Laws as prescriptive; imperatives Nature ○ Laws as descriptions I. What is a law of nature? Laws of nature are discovered ○ We discover that nature works that way, and what we create are the formulations of these uniformities Laws are still empirical statements, just a more specific and special class of it ○ Remember, empirical statements are “Any statement whose truth can be confirmed by observation of the world” So what makes laws special? ○ They are at the core of the empirical sciences II. Features of Laws of Nature: First Feature “Several features are usually counted as defining of laws of nature, but not everyone agrees that all of them are defining” First feature: A law of nature is a universal statement ○ It is in the form of “All A’s are B’s” ○ Ex. “All lead melts at 327.5 C”, “All iron rusts when exposed to oxygen” II. Features of Laws of Nature: Second Feature Second feature: A law of nature must be open-ended ○ It is open in terms of having unlimited range across time and space ○ Ex. When we discover that a previous law “water boils at 100 C” is falls at mountaintops, we create a new law which is the relation between the pressure and boiling point. II. Features of Laws of Nature: Third Feature Third feature: A law of nature must be expressible as hypothetical statements Consider the two statements. One is based on a law, the other is not ○ “If there were a crow, it would be black” Based on our observation that all the crows we have seen is black ○ “If this were a stone, it would fall” Based on the law of gravity, under specific conditions II. Features of Laws of Nature: Fourth Feature Fourth feature: the greater the generality, the more likely it is to be accorded the status of a law of nature Some laws could be described merely as “low-level generalizations” ○ If melting point of lead were different, it would not change much in the universe ○ If birds had three legs, this wouldn’t affect much besides birds II. Features of Laws of Nature: Fourth Feature Compare it with “If there is friction, then always, there is heat” ○ It is much more fundamental since it is concerned with molecular motion Most famous example of a law of nature, Newton's laws of nature ○ It is a claim about every bit of matter in the universe ○ It concerns motions from apples, to planets, to stars, and to galaxies ○ Although gravity is sometimes also called a theory. Hospers admits that the boundary is not sharp III. Laws of Nature: Overall Knowledge of laws enables us to predict future occurrences and events But laws are not perfect and sometimes require correction or qualification ○ Some aspects of Newton’s laws was modified by Einstein’s theory ○ So at this point, the most secure prediction of gravity is Einstein’s theory… at least for now Explanation I. Explanation: In the context of science There is ambiguity in asking for an “explanation” Questions related to “why?” ○ “Why is the door open?” Questions related to clarification ○ “Can you explain that concept to me?” Questions related to how ○ “Can you explain how to turn the TV on?” I. Explanation: In the context of science For science, we are mostly concerned with explaining “why?” ○ “Scientific knowledge allows us to explain why many things occur as they do” ○ In explaining why, we need theories Laws of nature do not answer why, they only describe ○ Theories that invoke entities in the explanation which could not be observed by the senses Theories I. What are theories? They are never deductively proven, only inductively confirmed ○ Take for example these two arguments with the same logical structure, I. What are theories? Science is technically a logical fallacy of “affirming the consequent” in the sense that it can never provide logical certainty. ○ In terms of observed facts, what theories can do is to provide an explanation that could be confirmed to some degree or other ○ What this means is that we do not prove theories by logical “deduction” It is confirmed through “induction” II. Inductively confirming theories With regular statements, there may be countless observations to verify it, but only one example is needed to render it false ○ “All swans are white” You may see white swans all your life to confirm your observations. But all it takes is seeing one black swan to falsify it II. Inductively confirming theories In theory, after we have accepted a given theory, it is not enough for a single observation to immediately disprove it ○ Ex. Imagine a large star suddenly approached our sun but it had no discernible gravitational effects, would we immediately abandon our understanding of Newton’s law and Einstein’s theory? No, we would try to find explanations within our theories or other generally accepted theories. Perhaps it is a dark star, or a star with small mass, etc. II. Inductively confirming theories In general, our attitude towards theories and laws is that we assume to have “ceteris paribus” (other things being equal) ○ If something is not equal, the theory is not immediately dismantled. Only the current prediction is refuted Scientific theories require a lot of empirical observation ○ But it requires even more to tear them down since they can be preserved despite strong evidences against them. II. Inductively confirming theories This is because of coherence, scientific theories are not alone in supporting themselves ○ Statements within each theories are interdependent on other theories. Doubting one statement has effects of doubting the others since it is a system. II. Inductively confirming theories III. Changing laws and theories One example of a law that has been refuted is the “law of conservation of matter” ○ This law states that “the total amount of matter in the universe remains always the same” This has been abandoned in favor of the “law of conservation of energy”. Since matter can be turned into energy, the amount of total matter could decrease. ○ This law states that “the total amount of energy in the universe remains the same” III. Changing laws and theories In general, when evidence seems to attack a well-established theory, we try and find other reasons why it might be the case It requires a massive amount of disconfirmation before we abandon theories IV. A Theory in Astronomy: Ptolemaic theory vs Copernican theory Both theories explained the movement of the planets and were able to accurately predict eclipses. But Ptolemy’s theory was more burdensome in that new epicycles had to be hypothesized and calculated when initial predictions are off Copernicus’ theory worked much better, but at the time it was being disconfirmed by the lack of parallax among the stars ○ Copernicus died in 1543, and parallaxes were only discovered on 1838. IV. A Theory in Astronomy: Ptolemaic theory vs Copernican theory Here we can see how two theories are set against each other The simpler theory requiring fewer general principles is most likely to be accepted But the simplicity’s ability to explain still needs to be strong, otherwise the more complicated theory will be favored Ockham’s razor - “Entities are not to be multiplied without necessity” Possibility I. Possibility: Empirical possibility Empirical possibility What we mean by its impossibility is that it defies the laws of nature ○ Although a lot of things that scientist used to claim were empirically impossible, has become possible as our knowledge expands It used to be deemed empirically impossible for objects heavier than air to fly Currently, it is empirically impossible for anything to exceed the speed of light II. Possibility: Technical possibility Technical possibility This possibility depends on human ability to apply laws of nature in inventing new things. Our “technique” of leveraging the laws of nature It is with how we use the laws of nature Example. While laws of nature permit travelling to Pluto. At this time, it is technically impossible for our spaceships to bring people there. III. Possibility: Logical possibility Logically possibility This possibility concerns the logical structure of statements and whether or not it contains contradiction ○ Example. “an object travels 200,000 miles per second, exceeding the speed of light” ○ It is logically possible because it contains no contradiction III. Possibility: Logical possibility Logically possibility An example of a logical impossibility is this: ○ A tower is both 100 feet high and 150 feet high at the same time ○ A square can contain curved lines These are impossible by definition and breaks the fundamental rules of logic ○ Remember the rules of identity, non-contradiction, and excluded middle