Philosophy of Knowledge & Reality

PHILOSOPHY OF KNOWLEDGE & REALITY

WEEK 5 – DAY 1: TIME TRAVEL & FREE WILL REVIEW: EPISTEMOLOGY

What is Kant’s “Copernican Revolution”?

Mind structures perception of reality within it’s pre-existing ideas:

Time Space THE HISTORY OF TIME: PRE-MODERN TIME

1. Change & The Cycles of Nature (making the world more predictable and ordered) WHAT IS TIME? MODERN TIME

2. Galileo & Newton’s Time (Pre-Einstein)

• We had objects that existed in 3-dimensional space. • That moved forward in linear time. • So, motion described by independent entity: time. • Space and time were separate. The passage of time (i.e. 60 seconds) was constant, and had nothing to do with motion. WHAT IS TIME? MODERN TIME

3. Einstein’s Time But Einstein changed all of that…

• Said time was another dimension, just like width, length, height. • Time no longer constant, but dependent upon motion through space (like all other dimensions). WHAT IS TIME? MODERN TIME

3. Einstein’s Time http://www.youtube.com/watch?v=opgMv6fcYRM EINSTEIN’S TIME

What are some strange implications of this?

1. Time travel possible?

2. … PHILOSOPHY OF TIME TRAVEL (PARADOXES GALORE)

Is Time Travel Philosophically Possible? Arguments Against Time Travel

1. Self-Contained Loops: (All You Zombies) PHILOSOPHY OF TIME TRAVEL (PARADOXES GALORE)

All You Zombies http://learnodo-newtonic.com/all-you-zombies-paradox-robert-heinlein DISCUSSION

Summarize the short story “All You Zombies” and explain how it could be used to argue that time travel may not be possible. PHILOSOPHY OF TIME TRAVEL

All You Zombies http://learnodo-newtonic.com/all-you-zombies-paradox-robert-heinlein PHILOSOPHY OF TIME TRAVEL

All You Zombies Is this possible?

You are your own mom …and dad …and grandfather …and grandmother ..and…and…and…

He/she is his/her own family tree!! ARGUMENT AGAINST SELF-CONTAINED LOOPS

• P1) If time travel is possible, then there could theoretically exist self-contained time loops. • P2) Self-contained time loops are not possible. • C) Therefore, time travel must not be possible

Supporting P2 1. Backward Causation Argument 2. No Destination Argument 3. In Two Places at Once Paradox PHILOSOPHY OF TIME TRAVEL (PARADOXES GALORE)

Is Time Travel Philosophically Possible? Arguments Against Time Travel

1. Self-Contained Loops (All You Zombies) 2. Changing the Past Paradox (Grandfather Paradox) CHANGING THE PAST PARADOX (THE GRANDFATHER PARADOX) THE GRANDFATHER PARADOX (FORMAL ARGUMENT)

• P1) If time travel is possible, then you could kill your grandfather (before he had kids) • P2) It is impossible for you to have existed if you succeed in killing your grandfather (before he had kids) • C) Therefore, time travel must not be possible

How could you solve this paradox? REPLYING TO CHANGING THE PAST PARADOX: SOLUTION #1

• Denying P1: Time travel is possible, but you do not and cannot kill your grandfather

When you time travel, you can affect the past, but only because you already did

• This works in “All You Zombies”, but • This justification doesn’t work this time • E.g. If you had already been there and killed your grandfather… then you would never have existed REPLYING TO CHANGING THE PAST PARADOX: SOLUTION #2

• Denying P1: Time travel is possible, but you do not and cannot kill your grandfather When you time travel, you can attempt to kill your grandfather, but you will never succeed (somehow). Universe won’t let you. REPLYING TO THE GRANDFATHER PARADOX: SOLUTION #3

• Denying P1: Time travel is possible, but you do not and cannot kill your grandfather

When you time travel, you create a new alternate universe. PHILOSOPHY OF TIME TRAVEL (CHANGING THE PAST PARADOXES)

Common Solution – Alternative Timelines

Today Inspired to build time machine

Take you off their will Get into TM: Parents divorce Let’s go back and retake the exam! Crashed your car

Yesterday Failed Exam But you can’t change your own past right? Time PHILOSOPHY OF TIME TRAVEL (CHANGING THE PAST PARADOXES)

Common Solution – Alternative Timelines

Today

But is this really “time traveling” or just universe jumping?

Yesterday For time travel to be Time meaningful does it have to be to our own past? PHILOSOPHY OF TIME TRAVEL (PARADOXES GALORE)

Is Time Travel Philosophically Possible? Arguments Against Time Travel

1. Self-Contained Loops: (All You Zombies) 2. Changing the Past Paradox (Grandfather Paradox) 3. No Tourist Argument NO TOURIST ARGUMENT WHERE ARE THE TIME TRAVELERS, THEN?

• P1) If time travel is possible, then we should see time travelers visiting us. • P2) We don’t see time travelers visiting us.

• C) Therefore, time travel must not be possible

How could you address this objection? NO TOURIST ARGUMENT SOLUTION #1

• Accept the argument

• It’s true that there are no time travelers… but only because: • Global warming, or • Nuclear war, or • Super-viruses, or • The robotic uprising of the (very) late nineties…

• … killed off all of the humans before we got around to making time machines! NO TOURIST ARGUMENT SOLUTION #2 • Denying P2: There is evidence of time travelers!

• John Titor www.johntitor.com • That guy who went under his sink (Hakan Nordkvist) • http://www.youtube.com/watch?v=qBUv4j3DINE • That mullet guy PHILOSOPHY OF TIME TRAVEL

Discussion:

• Based on the philosophical arguments and paradoxes covered in class, does time travel seem logically possible to you? Why? • What would Kant say about that? EINSTEIN’S TIME

What are Some Strange Implications of This?

1. Time travel possible?

2. Future already set? • If so, do we have any choice in the matter? PHILOSOPHY OF KNOWLEDGE & REALITY

WEEK 5 - DAY1 – HR 2 CHOICES

Let’s list examples of “choices” you made today. REVIEW: EINSTEIN’S TIME

What are some strange implications of this?

1. Time travel possible?

2. Future already set? WHAT DO YOU BELIEVE?

• Do you believe in cause and effect – that every event has a cause?

• Do you believe your behavior is determined by your genes and past experience?

• Do you believe in a completely material world (devoid of an immaterial spirit or soul)?

• Do you believe in the laws of physics?

• Do you believe in an all-knowing God?

• Do you believe in destiny or fate?

Problem: If you said yes to any of these, you may have a problem justifying the existence of free will. THE BIG QUESTION

Do you have free will? FREE WILL

What do you think this means?

Popular Definitions: • The ability to freely and consciously choose between two or more options, either on the spot or after deliberation. • The ability to have chosen differently than we did.

Let’s see in the film – (0:00-16:00) DETERMINISM

Precrime Unit is Founded on Determinism

Determinism: • The future is fixed (“determined”) by the past. • The past causes the future.

Why do we say the pre-crime unit is based on determinism? DETERMINISM

Based on Belief in “Cause & Effect” BACK TO THE FILM… FREE WILL VS. DETERMINISM CAN THEY CO-EXIST?

1. Incompatibilism 2. Compatibilism Free will and determinism Free will and determinism cannot co-exist. can co-exist.

1. Hard Determinism 1. Traditional (No FW) Compatibilism 2. Indeterminism (FW Possible) 2. Deep Compatibilism 3. Libertarianism (FW Possible)