Philosophyspeaking topic
The grandfather paradox: travel back in time and stop your own grandfather from ever meeting your grandmother, and you are never born; but if you are never born, you cannot go back to stop him. Does this logical loop make time travel impossible from the start?
— the grandfather paradox
practice with this topic
Set the timer (5-30 min), take 20 seconds of prep if you like, start talking. Jot your thoughts onto the sticky-note board.
similar topics
- The fool pursues the pleasures of life and finds himself their dupe; the wise man avoids its evils.
- Heraclitus says you cannot step into the same river twice, because the water has flowed on. But think again: is it only the river that changes, or is the person stepping in also someone new? Can anyone step into any river even once?
- The odds of you existing were practically zero; you happened only through countless accidents stacking up just right. Given such an impossible stroke of luck, is living an ordinary life a waste of the universe's gift, or is even thinking that way an empty vanity?
- Hilbert's infinite hotel: a hotel with infinitely many rooms is completely full, yet a new guest can still be given a room. Why does our common sense collapse the moment 'full' and 'infinite' appear in the same sentence?
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