Extraterrestrials & the Digital Universe -Von Neumann & Edward Teller

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Hello,

I’ve been reading George Dyson’s Turing’s Cathedral lately & today I read something interesting about intelligent life & computers from the age of John von Neumann & Edward Teller, which I’d like to share [1]:

Von Neumann rarely discussed extraterrestrial life or extraterrestrial intelligence; terrestrial life and intelligence were puzzling enough.

…”There is every reason to believe that any planet on which a large variety of molecules can reproduce by interconnected (or symbiotic) autocatalytic reactions, may see the formation of organisms with the same properties.” One of these properties, independent of the local conditions, might be the development of the Universal Machine.
Over long distances, it is expensive to transport structures, and in expensive to transmit sequences. Turing machines, which by definition are structures that can be encoded as sequences, are already propagating themselves, locally, at the speed of light.

…Those best able to survive the passage of time, adapt to changing environments, and migrate across interstellar distances will become the most widespread. A life form that assumes digital representation, for all or part of its life cycle, will be able to travel at the speed of light. As artificial intelligence pioneer Marvin Minsky observed on a visit to Soviet Armenia in 1970, “Instead of sending a picture of a cat, there is one area in which you can send the cat itself.” [p.290]

The host planet would have to not only build radio telescopes and be actively listening for coded sequences, but also grant computational resources to signals if and when they arrived. The SET@home network now links some five million terrestrial computers to a growing array of radio telescopes, delivering a collective 500 teraflops of fast Fourier transforms representing a cumulative two million years of processing time. Not a word (or even a picture) so far -as far as we know. [p.291]

In a discussion with Edward Teller, the authors quotes Teller:

 “…If there is life in the universe, the form of life that will prove to be most successful at propagating itself will be digital life; it will adopt a form that is independent of the local chemistry, and migrate from one place to another as an electromagnetic signal, as long as there’s a digital world -a civilization that has discovered the Universal Turing Machine- for it to colonize when it gets there. [p.292]

IPython: Python at your fingertips

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To install the IPython notebook, do the following:

sudo apt-get install distribute ipython python-zmq python-tornado ipython-notebook
pip install numpy matplotlib #if you want to use the numpy extension & matplotlib plotting library
ipython notebook # launch the notebook from a terminal (will open in browser!)

 

The History of FORTRAN

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Interviews with the original developers of FORTRAN back in the 1950s.

other source: http://www.fortranlib.com/FORTRAN-1982.wmv

Philosophy: Kant (Prolegomena)

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I was just reading the author’s introduction to “Immanuel Kant: Prolegomena to Any Future Metaphysics” in the book “The Great Works of Philosophy” by Robert Paul Wolf [1]. I want to share the last section (pp. 347-348) of this 3-page intro:

“…If the  mind imposes its own subjective forms on nature, then the nature it knows cannot be a realm of things as they are in themselves; it must be merely a realm of things as they appear to us. In short, our knowledge must be limited to appearances; reality is forever obscured from our view. Hence metaphysics, the “science of reality,” must be an empty discipline, a mere pretension and illusion to be refuted rather than encouraged.
Thus Kant’s philosophy is at one and the same time optimistic and pessimistic. He reassures us that our mathematics and science is valid knowledge, but he cautions us that it is valid only for appearances, not for reality itself. In the end, the transcendental philosophy is a lesson in intellectual humility, for it teaches us that the human mind lacks the power to penetrate the veil of appearance and grasp the inner nature of independent reality.”

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Thanks for reading

Useful Unix/Linux commands

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$ indicates terminal command
# indicates a comment
Bold indicates “not installed by default”
$ lsusb     #list USB devices
$ lspci     #list all PCI devi
$ startx    #initialize an X session
$ more      #filter for paging through text one screenful at a time. (less gives more advanced).
$ less      #opposite of more; allows backward movement in the file as well as forward movement.
$ stty      #change and print terminal line settings
  $ stty size # prints terminal size

File commands

$ locate            #find files by name (for newbies I suggest the gui catfish -requires installation)
$ find              #search for files in a directory hierarchy
$ ls                #list directory contents
$ cd                #change directory
$ pwd               #print name of current/working directory
$ cp                #copy files and directories
$ rm                #remove files or directories
$ rmdir             #remove empty directories
$ file foo.format   #extracts info about file and what software it was written with; helpful in the case of having forgot which software was used to produce such a file

System info

$ uname
$ df                         #report file system disk space usage
                             #e.g; df or df /home
$ man                        #interface to the on-line reference manuals
$ free                       #Display amount of free and used memory in the system
                             #e.g; free -mt (m for MB & t for totals line)
$ uptime                     #tell how long the system has been running.
$ finger                     #user information lookup program
$ w                          #show who is logged on and what they are doing.
$ whoami                     #print effective userid
$ cat /proc/meminfo          #memory info
$ cat /proc/cpuinfo          #cpu info
$ lsb_release -a             #print (a: all ) distribution-specific information
$ last -x | grep shutdown    #show listing of last 10 logged in users; you can pipe this to the tail to read the last n instances.
                             #e.g; for 10 instances: last -x | grep shutdown | tail -n 10
$ last -x | grep reboot      #show listing of last logged in users
$ sudo shutdown -P hh:mm     #shutdown & poweroff (-P) @ hh:mm

Processes

$ uname
$ ps               #report a snapshot of the current processes.
$ top              #display Linux tasks
$ htop             #interactive process viewer based on top
$ watch            #execute a program periodically, showing output fullscreen
                   #e.g; watch -n 5 free -m
$ powertop         #program to analyze power consumption on Intel-based laptops
$ kill pid         #send a signal to a process
$ killall proc     #kill processes by name
$ pidof program    #find the process ID of a running program

Some useful terminal shortcuts

Ctrl+C #halt the current command
Ctrl+Z #pause command
$ fg #resume paused command in foreground bg resume paused command in background
Ctrl+D #logout of current session (similar to exit)
Ctrl+W #erase last word before cursor
Ctrl+U #erases the whole line
Ctrl+R #type to bring up a recent command
I hope this list turns out to be useful to you 🙂

Thanks for reading

last update: 2014-11-03