If something happened, it happened

Discover Magazine’s 10+1 rules for time travelers:

0) There are no paradoxes.
1) Traveling into the future is easy.
2) Traveling into the past is hard — but maybe not impossible.
3) Traveling through time is like traveling through space.
4) Things that travel together, age together.
5) Black holes are not time machines.
6) If something happened, it happened.
7) There is no meta-time.
8) You can’t travel back to before the time machine was built.
9) Unless you go to a parallel universe.
10) And even then, your old universe is still there.

(via Buzzfeed).

20 sculptures/hour

I decided to start posting a bit more this week after I realized over the weekend that I now have more items saved to recommend to you in the future than all the total items I have previously recommended to you in the past. This is an attempt to balance things out a bit. Realizing I’ve done 20 posts in four days, I couldn’t help but be reminded of Lydia Davis’s fantastic story “20 Sculptures in One Hour” from her collection Varieties of Disturbance (mentioned on L&UL here), which I cannot seem to find online but, believe me, is well worth a read.

Here’s a good snapshot of the super-short story from an interview with Davis:

Lydia: An hour is a long time, but if there are 20 sculptures that you have to look at within an hour, that’s 3 minutes per sculpture, which isn’t a long time at all. And yet, three minutes can end up feeling like a long time…
Interviewer: Sounds like Zeno’s Paradox.
Lydia: I love Zeno’s Paradox!

Now reminded of paradoxes, I’m resolving to make my first post tomorrow (#21, if you’re counting) a long-overdue list of all paradoxes mentioned by Peter Cave on this episode of Philosophy Bites dedicated to the subject. Stay tuned.


The Drake Equation is “an attempt to estimate the number of extraterrestrial civilizations in our galaxy with which we might come in contact.” It was theorized by Dr. Frank Drake, who is best known for being the founder of SETI, or the Search for Extra-Terrestrial Inteligence. Drake proposed the equation in 1960, the same year the physicist Enrico Fermi proposed his Fermi Paradox, which asks why “if a multitude of advanced extraterrestrial civilizations exist in the Milky Way galaxy, evidence such as spacecraft or probes are not seen.” One suggestion for the reason for this is called the Zoo Hypothesis, which suggests that aliens may be present but that they might “generally avoid making their presence known to humanity, or avoid exerting an influence on human development, somewhat akin to zookeepers observing animals in a zoo.” Another suggestion is known as The Great Filter, which “acts to reduce the great number of potential sites to the tiny number of intelligent species actually observed (currently just one: ours). It might work either by one or more barriers to the evolution of intelligent life, or a high probability of self-destruction.” While SETI implies a more passive search, METI (Messaging to Extra-Terrestrial Intelligence), is described as follows: “The science known as SETI deals with searching for messages from aliens. METI science deals with the creation of messages to aliens. […] [METI] pursues not a local and lucrative impulse, but a more global and unselfish one—to overcome the Great Silence in the Universe, bringing to our extraterrestrial neighbors the long-expected annunciation ‘You are not alone!’” Attempts at METI include the beautiful Arecibo Message and the highly symbolic Pioneer Plaque, both well worth a look.