16 ms·

John McCarthy’s collection of numerical facts for use in elisp programs

279 points by chrchr 3y ago

jaykru 3y ago
"It contains a lot of units conversions and also astronomical facts that I needed for some research on moving Mars to a more temperate location." lmfao, anywhere I can read more about McCarthy's plans for this?
- wgrover 3y ago
  http://www-formal.stanford.edu/jmc/future/mars.pdf http://www-formal.stanford.edu/jmc/future/mars.pdf
  - MichaelMoser123 3y ago
    Wow, thank you! This made my day: "Consider the possibility that introducing an arbitrarily small tame asteroid could throw a planet out of the solar system. This would be a different kind of instability than those that have been so far considered. It would be of mathematical interest to prove that a system consisting of a sun and three planets could be disrupted by a single arbitrarily small tame asteroid."
  - MichaelMoser123 3y ago
    [flagged]
    - BearhatBeer 3y ago
      Careful, AI has been known to lie.
      - MichaelMoser123 3y ago
        I know, still I an not sure what is better, asking an LLM or googling? (google search has been quietly deteriorating)
        ChuckMcM 3y ago
        As time progresses "better" becomes "going to the public library and working with a research librarian to figure it out."
        dubya 3y ago
        LLM then Google? "The greening of Mars" is not by Stanley Robinson, but by James Lovelock and Michael Allaby. It doesn't appear to feature moving Mars, but terraforming it using 80's technology. I don't think "Green Mars" by Robinson has Mars being moved either. There's nothing on Google for Benford and "Martian Transfer", though it's possible he wrote such a story with a different title.
        Dylan16807 3y ago
        LLM approximates throwing the google snippets into a blender so that you can't evaluate anything and the nouns are very likely to get swapped. Googling is much better.
  - twic 3y ago
    Hans Moravec is really into space elevators. Is there some correlation between being an AI researcher and having an interest in space mega-engineering?
    - Sharlin 3y ago
      Almost certainly, simply because they both strongly correlate with being geeks. And SF geeks in particular. And the very particular sort of hard SF geek who feels right at home at Shock Level 4 [1]. [1] http://sl4.org/shocklevels.html http://sl4.org/shocklevels.html and literally on http://sl4.org/ http://sl4.org/
    - dekhn 3y ago
      yes, it's known as the nerd space elevator strange attractor. It is frequently observed in nature with its related chaotic entities, the national-scale DC power grid attractor, and the singularity attractor (some argue that all these attractors are really just specific instances of the singularity attractor).
    - gumby 3y ago
      It's a nice hard problem with lots of juicy subproblems that you can work on even through the central problem (materials science) is nowhere near being solvable.
    - martincmartin 3y ago
      John McCarthy was Moravec's PhD advisor.
  - zorked 3y ago
    This is considerably more interesting that the original link...
  - effed3 3y ago
    I wonder what will happen to the others planets, on a long scale... in a dynamical (chaotic) system stability is not granted, probably a bunch of asteroids-tools are needed to correct the deviation of all others planets form a desired configuration.
  - cbsks 3y ago
    The sci-fi book practically writes itself. A wealthy entrepreneur puts an asteroid in motion to move mars and sets up a long term foundation to keep it operational for the next 40,000 years. In conjunction with the orbital adjustment, terraforming begins and the first enclosed permanent settlements are founded. After the orbital changes are complete, the new planet is open for human development and is renamed from Mars to Musk, after its visionary founder.
    - coldtea 3y ago
      Of course things go horribly wrong, and Mars crashes into earth. The moral of the story being if you don't have ultra-superior technology and experience doing the same thing outside of your own solar system and checking the results to adjust your procedures, then nudging things and seeing what happens at planetary scale is playing with fire.
    - justinjlynn 3y ago
      Is there any better embodiment of entrepreneurial capitalism than stealthily appropriating an entire planet, privatising it, and then naming it after one's self? ... I'd be hard pressed to think of one.
    - OneDonOne 3y ago
      I thought it was the short stories "Sunken Gardens" and "Cicada Queen" by Bruce Sterling from his Shaper/Mechanist universe. Oh well.
- WalterBright 3y ago
  Maybe an easier job would be to cool Venus by blocking sunlight from reaching it. Then, terraform it.
  - chimpanzee 3y ago
    But me big man. Me move mars.
  - virtue3 3y ago
    And then you get a world bathed in eternal darkness until you control it's greenhouse gas atmosphere? I think it would be easier to just limit greenhouse gas emissions on earth. Your point works pretty well considering that Venus has a a dense atmosphere unlike Mars.
    - kleer001 3y ago
      It certainly would. However, these are centuries long plans. A path along which the local issues will be solved.
    - WalterBright 3y ago
      Just need to reduce the solar incidence, not eliminate it. The same technology could be used to reduce gw on the earth: 1. an orbiting sunshade 2. putting something in the atmosphere that makes it more reflective, like sulfur dioxide I wonder how big a sunshade would need to be to reduce temps by, say, one degree. A specific location could be shaded by putting the shade in geosynchronous orbit. To finance the sunshade, put a Starbucks or Coca-Cola logo on it.
      - bee_rider 3y ago
        Or a giant “Welcome to Disney’s World.”
        Hikikomori 3y ago
        Since so many believe aliens are here already we might as well start advertising to them.
- microtherion 3y ago
  Maybe it's for the better that McCarthy passed away in 2011; if he were still alive, he might have gotten a grant from SpaceX to put his scheme into action.
  - CyberDildonics 3y ago
    Does spaceX give out grants to programmers?
  - xdavidliu 3y ago
    I think you mean "put his emacs lisp into action"
behnamoh 3y ago
[flagged]
- vjust 3y ago
  All Lisp related stories, especially those that refer to the creator of Lisp, get automagically upvoted.
- AnimalMuppet 3y ago
  Because some people find it interesting. Same as everything else on HN's front page.
Bostonian 3y ago
I guess if you want a library for linear algebra operations in Lisp, you just write them yourself. From McCarthy's collection: ;;; multiplying a matrix by a column vector (defun mvmult (matrix vector) (list (scap (nth 0 matrix) vector) (scap (nth 1 matrix) vector))) ;;; sum of two vectors (defun vplus (vec1 vec2) (list (+ (nth 0 vec1) (nth 0 vec2)) (+ (nth 1 vec1) (nth 1 vec2)))) ;;; difference of two vectors (defun vminus (vec1 vec2) (list (- (nth 0 vec1) (nth 0 vec2)) (- (nth 1 vec1) (nth 1 vec2)))) ;;; scalar product of two vectors (defun scap (vec1 vec2) (+ (* (nth 0 vec1) (nth 0 vec2)) (* (nth 1 vec1) (nth 1 vec2)))) ;;; product of scalar and vector (defun svmult (sca vec) (list (* sca (nth 0 vec)) (* sca (nth 1 vec)))) ;;; sum of a list of vectors (defun addup (veclist) (if (null veclist) zerovec (vplus (car veclist) (addup (cdr veclist))))) (defconst zerovec '(0 0) "zero vector with two components"1) ;;; length of a vector (defun length (x) (sqrt (+ (expt (nth 0 x) 2) (expt (nth 1 x) 2)))) (defconst Imatrix '((1.0 0.0) (0.0 1.0)) "unit 2x2 matrix") (defun smmult (sca matrix) (list (svmult sca (nth 0 matrix)) (svmult sca (nth 1 matrix)))) (defun mplus (mat1 mat2) (list (vplus (nth 0 mat1) (nth 0 mat2)) (vplus (nth 1 mat1) (nth 1 mat2)))) (defun mminus (mat1 mat2) (list (vminus (nth 0 mat1) (nth 0 mat2)) (vminus (nth 1 mat1) (nth 1 mat2)))) (defun mmult (mat1 mat2) (list (list (scap (nth 0 mat1) (col 0 mat1)) (scap (nth 0 mat1) (col 1 mat1))) (list (scap (nth 1 mat1) (col 0 mat1)) (scap (nth 1 mat1) (col 1 mat1))))) (defun multiplyup (matlist) (if (null matlist) Imatrix (mmult (car matlist) (multiplyup (car matlist) (multiplyup (cdr (matlist)))))))
- BaculumMeumEst 3y ago
  see also https://github.com/jb55/vrscript-samples/blob/master/vr.rkt https://github.com/jb55/vrscript-samples/blob/master/vr.rkt
- zelphirkalt 3y ago
  Of course one can do this and it might work as a stopgap solution and abstraction layer until something different comes along and I have done similar, but ultimately this will not be very efficient. It might be a better, albeit less beautiful, solution to use any low level language inplemented linear algebra bindings for the lisp at hand. Hopefully there existing one.
bitwize 3y ago
What's interesting to me is that the creator of Lisp found Emacs Lisp acceptable for practical general use. (Although as noted this file can be loaded verbatim into Common Lisp and work fine.)
- Zambyte 3y ago
  McCarthy did not invent Lisp with the expectation that it even could be used as a language for real computers. Steve Russell had to convince him that McCarthy's theoretical definition of Lisp would actually work by actually implementing the interpreter himself. I don't think McCarty would have been too snobbish in dialects, considering he wasn't expecting a practical language at all :D
  - lispm 3y ago
    > McCarthy did not invent Lisp with the expectation that it even could be used as a language for real computers. He was expecting a practical language and was designing one. Lisp was from day zero a project to implement a real programming language for a real computer. Earlier he experimented with IPL and also list processing / functional programming in Fortran. The original plan was to implement a Lisp compiler. At first the Lisp code, which McCarthy was experimenting with, was manually translated to machine code. So before the first Lisp compiler or interpreter existed, he was experimenting with how to represent and make the code running on a computer. He then invented a Lisp interpreter in Lisp. Then came up the idea (-> Steve Russell) to use this EVAL as a base for an interpreter implementation, which was also implemented by manually translating the Lisp code to machine language. McCarthy at first thought that it was not possible to use this Lisp evaluator written in Lisp as a base, but Steve Russell implemented it. Around 1962 then a Lisp compiler followed. The paper by Herbert Stoyan describes the history of McCarthy's Lisp project: https://github.com/papers-we-love/papers-we-love/blob/main/comp_sci_fundamentals_and_history/early-lisp-history-1956-1959-herbert-stoyan-html-rendering.pdf https://github.com/papers-we-love/papers-we-love/blob/main/c... > considering he wasn't expecting a practical language at all :D He was expecting a practical language, since he was designing one and the team was implementing it. He designed data structures, core functions, evaluation, garbage collection as memory management, input and output, ... The language was to be used as a list processing language for research in the upcoming field of Artificial Intelligence: game play, natural language dialogs, symbolic maths (integration, ...), logic reasoning, computer vision, robotics, ... He wrote several design documents on the language and its implementation. There even is the Lisp I Programmer's Manual from March 1960: https://bitsavers.org/pdf/mit/rle_lisp/LISP_I_Programmers_Manual_Mar60.pdf https://bitsavers.org/pdf/mit/rle_lisp/LISP_I_Programmers_Ma... Lisp was initially developed for an IBM 704 computer and primitive list operations CAR (= FIRST, HEAD) and CDR (= REST, TAIL) were referencing machine architecture details of the IBM 704.
agnosticmantis 3y ago
Some may find it interesting that John McCarthy coined the term Artificial Intelligence and was called a/the father of AI before the deep learning folks took over. This AI referred to the symbolic flavor not the connectionist one. Nowadays (god-)fathers of AI are Geoff Hinton and Yann LeCun and others, but 20 years ago things were very different…
- morelisp 3y ago
  20 years ago symbolic reasoning was already called GOFAI and the hotness was Bayesian statistical reasoning. 40 years ago, maybe.
  - agnosticmantis 3y ago
    I was a kid back then, so not really aware of the cutting edge research happening in those days, but here’s for example the description of Russel & Norvig’s “Artificial Intelligence: A Modern Approach (2nd edition, published 2003)”: “The long-anticipated revision of this best-selling book offers the most comprehensive, up-to-date introduction to the theory and practice of artificial intelligence. Intelligent Agents. Solving Problems by Searching. Informed Search Methods. Game Playing. Agents that Reason Logically. First-order Logic. Building a Knowledge Base. Inference in First-Order Logic. Logical Reasoning Systems. Practical Planning. Planning and Acting. Uncertainty. Probabilistic Reasoning Systems. Making Simple Decisions. Making Complex Decisions. Learning from Observations. Learning with Neural Networks. Reinforcement Learning. Knowledge in Learning. Agents that Communicate. Practical Communication in English. Perception. Robotics. For those interested in artificial intelligence.”
    - morelisp 3y ago
      By necessity, textbooks lag the actual work in most fields. Nonetheless the titular “modern approach” is the statistical reasoning (plus a heavy focus on search over inference).
- fsckboy 3y ago
  > This AI referred to the symbolic flavor not the connectionist one that's not a fair characterization at all. The title contains the term "Artificial Intelligience", and soon after item 3 in the proposal was "Neuron Nets". The word symbolic is not used at all, although the term Abstractions is used. http://www-formal.stanford.edu/jmc/history/dartmouth/dartmouth.html http://www-formal.stanford.edu/jmc/history/dartmouth/dartmou... A PROPOSAL FOR THE DARTMOUTH SUMMER RESEARCH PROJECT ON ARTIFICIAL INTELLIGENCE J. McCarthy, Dartmouth College M. L. Minsky, Harvard University N. Rochester, I.B.M. Corporation C.E. Shannon, Bell Telephone Laboratories August 31, 1955 We propose that a 2 month, 10 man study of artificial intelligence be carried out during the summer of 1956 at Dartmouth College in Hanover, New Hampshire. The study is to proceed on the basis of the conjecture that every aspect of learning or any other feature of intelligence can in principle be so precisely described that a machine can be made to simulate it. An attempt will be made to find how to make machines use language, form abstractions and concepts, solve kinds of problems now reserved for humans, and improve themselves. We think that a significant advance can be made in one or more of these problems if a carefully selected group of scientists work on it together for a summer. The following are some aspects of the artificial intelligence problem: 1 Automatic Computers If a machine can do a job, then an automatic calculator can be programmed to simulate the machine. The speeds and memory capacities of present computers may be insufficient to simulate many of the higher functions of the human brain, but the major obstacle is not lack of machine capacity, but our inability to write programs taking full advantage of what we have. 2. How Can a Computer be Programmed to Use a Language It may be speculated that a large part of human thought consists of manipulating words according to rules of reasoning and rules of conjecture. From this point of view, forming a generalization consists of admitting a new word and some rules whereby sentences containing it imply and are implied by others. This idea has never been very precisely formulated nor have examples been worked out. 3. Neuron Nets How can a set of (hypothetical) neurons be arranged so as to form concepts. Considerable theoretical and experimental work has been done on this problem by Uttley, Rashevsky and his group, Farley and Clark, Pitts and McCulloch, Minsky, Rochester and Holland, and others. Partial results have been obtained but the problem needs more theoretical work. 4. Theory of the Size of a Calculation If we are given a well-defined problem (one for which it is possible to test mechanically whether or not a proposed answer is a valid answer) one way of solving it is to try all possible answers in order. This method is inefficient, and to exclude it one must have some criterion for efficiency of calculation. Some consideration will show that to get a measure of the efficiency of a calculation it is necessary to have on hand a method of measuring the complexity of calculating devices which in turn can be done if one has a theory of the complexity of functions. Some partial results on this problem have been obtained by Shannon, and also by McCarthy. 5. Self-lmprovement Probably a truly intelligent machine will carry out activities which may best be described as self-improvement. Some schemes for doing this have been proposed and are worth further study. It seems likely that this question can be studied abstractly as well. 6. Abstractions A number of types of ``abstraction'' can be distinctly defined and several others less distinctly. A direct attempt to classify these and to describe machine methods of forming abstractions from sensory and other data would seem worthwhile. 7. Randomness and Creativity A fairly attractive and yet clearly incomplete conjecture is that the difference between creative thinking and unimaginative competent thinking lies in the injection of a some randomness. The randomness must be guided by intuition to be efficient. In other words, the educated guess or the hunch include controlled randomness in otherwise orderly thinking. In addition to the above collectively formulated problems for study, we have asked the individuals taking part to describe what they will work on. Statements by the four originators of the project are attached. ... the paper continues ...
aj7 3y ago
Ok, a warmer Mars is desirable. But is Mars, in earth’s orbit, but on the opposite side of the sun, really closer?
- 0xfae 3y ago
  Closer in terms of what? Distance? delta-v to get there? Time to get there?
- _jal 3y ago
  > Ok, a warmer Mars is desirable. To humans.
  - serf 3y ago
    yeah, well that is the typical comparison one would make as a human.. you are a human, right?
    - deleted 3y ago
      [deleted]
- trwaw 3y ago
  Without a magbetosphere it's pretty useless. It would just lose its atmosphere again within a few hundred years.
  - bmitc 3y ago
    Agreed. It's the very definition of a dead planet, and there is even a high probability that it had life before Earth.
- lmm 3y ago
  In travel time, no. In energy cost, yes, but only if you're willing to wait a long time to get there. Also impossible to communicate with directly by radio.
mckn1ght 3y ago
I made a GitHub repo mirroring it: https://github.com/armcknight/john-mccarthy-numerical-facts https://github.com/armcknight/john-mccarthy-numerical-facts Also saw someone else just added it to one of theirs: https://github.com/bbarclay7/bb-emacs/blob/5858823bb033be113a4d98a969ff6923510ecc4e/lisp/facts.el https://github.com/bbarclay7/bb-emacs/blob/5858823bb033be113...
nxobject 3y ago
Now we know: John McCarthy used (x)emacs. Clearly an important revelation in the ongoing browser wars. /s (and not to minimize how genuinely interesting this is)
thsksbd 3y ago
Very cool, but I wonder why did he define foot as: (setq foot (* 0.3048 m)) And not (setq foot (* 12 inch)) It comes to the same thing, but inch is defined in metric as 2.54 cm and the foot is a derived unit of the inch. But this way it clearly spells out the dependency. Im not criticizing, it was his library for his use, I'm just wondering if there is there a deeper meaning beyond "God enough"?
- jwhitlark 3y ago
  Heh, the creator of Lisp probably was "God enough" to redef constants as he saw fit.
- melling 3y ago
  He wanted to work in meters? Closer to his final result? (setq km (* m 1000.0)) (setq cm (* m 0.01)) (setq foot (* 0.3048 m)) (setq ft (* 0.3048 m)) (setq mile (* 5280 foot))
  - traes 3y ago
    The very snippet you gave there is a counterexample to your argument. He defines miles in terms of feet (which is in turn defined by meters) allowing him to use commonly known conversion factors as a sanity check, while still keeping all values in meters. If he had used his already present definition of an inch as 0.0254 meters to define feet, he could have compounded this even further. The true answer is almost certainly that he simply did whatever came to mind first, and didn't think of defining feet in terms of inches because he hadn't defined inches yet.
    - thsksbd 3y ago
      I mean the legal definition of the inch is 25.4 mm. All other imperial length units are derived from the inch. Furthermore, there are more than one definition of the inch. If he worked on astronomical data from the 19th century UK, all these units would have to be changed. By tying the foot to the inch he'd only have to redefine the inch to the old British inch.
dkbrk 3y ago
This might come in handy but it's much inferior to the frink units file [0] which is much more complete, more rigorous, and includes dimensions. [0]: https://frinklang.org/frinkdata/units.txt https://frinklang.org/frinkdata/units.txt
- bsza 3y ago
  That rant about the hertz is HN top material in and of itself.
- Archit3ch 3y ago
  > I think the candela is a scam
- mock-possum 3y ago
  Oh my god this is incredible
Exuma 3y ago
One thing I always wonder is how people throughout history, on famous historic codebases etc, can indent things.... 90% the way, and then out of dozes of things correct there will be 3 things that are painfully off. Man, just indent them all the way if youre going to do it halfway Ive seen this in dennis richie code, doom code, etc Am i the only person who sees these things stand out like a sore thumb? It would drive me mad. They either all have to be not aligned, or aligned, but not 90%
Exuma 3y ago
pony := 1 floz jigger := 1.5 floz
CyberDildonics 3y ago
Are equations being renamed to 'numerical facts' now?
kagevf 3y ago
So, I know that elisp has historically lacked lexical scope, so setting variables without a prefix has the potential for name clashes since even a variable setq'd into existence inside a defun will be added to the global namespace. I did an experiment to double check it's still true in a recent-ish emacs: (defun my-fun () (setq test-123-456 'this-is-a-test)) (my-fun) test-123-456 => this-is-a-test There is some information in the info file under elisp about lexical binding, but you can just use let to keep variables in a lexical scope. (defun my-other-fun () (let ((test-789 'this-is-another-test)) test-789)) (my-other-fun) test-789 => *** Eval error *** Symbol’s value as variable is void: test-789
shric 3y ago
Some of the constants have changed over the years. > (setq avogadro 6.0221367e23) ; Avogadro number This is now standardized to exactly 6.02214076e23

279 points by chrchr 3y ago

"It contains a lot of units conversions and also astronomical facts that I needed for some research on moving Mars to a more temperate location." lmfao, anywhere I can read more about McCarthy's plans for this?

wgrover 3y ago
http://www-formal.stanford.edu/jmc/future/mars.pdf http://www-formal.stanford.edu/jmc/future/mars.pdf
- MichaelMoser123 3y ago
  Wow, thank you! This made my day: "Consider the possibility that introducing an arbitrarily small tame asteroid could throw a planet out of the solar system. This would be a different kind of instability than those that have been so far considered. It would be of mathematical interest to prove that a system consisting of a sun and three planets could be disrupted by a single arbitrarily small tame asteroid."
- MichaelMoser123 3y ago
  [flagged]
  - BearhatBeer 3y ago
    Careful, AI has been known to lie.
    - MichaelMoser123 3y ago
      I know, still I an not sure what is better, asking an LLM or googling? (google search has been quietly deteriorating)
      - ChuckMcM 3y ago
        As time progresses "better" becomes "going to the public library and working with a research librarian to figure it out."
      - dubya 3y ago
        LLM then Google? "The greening of Mars" is not by Stanley Robinson, but by James Lovelock and Michael Allaby. It doesn't appear to feature moving Mars, but terraforming it using 80's technology. I don't think "Green Mars" by Robinson has Mars being moved either. There's nothing on Google for Benford and "Martian Transfer", though it's possible he wrote such a story with a different title.
      - Dylan16807 3y ago
        LLM approximates throwing the google snippets into a blender so that you can't evaluate anything and the nouns are very likely to get swapped. Googling is much better.
- twic 3y ago
  Hans Moravec is really into space elevators. Is there some correlation between being an AI researcher and having an interest in space mega-engineering?
  - Sharlin 3y ago
    Almost certainly, simply because they both strongly correlate with being geeks. And SF geeks in particular. And the very particular sort of hard SF geek who feels right at home at Shock Level 4 [1]. [1] http://sl4.org/shocklevels.html http://sl4.org/shocklevels.html and literally on http://sl4.org/ http://sl4.org/
  - dekhn 3y ago
    yes, it's known as the nerd space elevator strange attractor. It is frequently observed in nature with its related chaotic entities, the national-scale DC power grid attractor, and the singularity attractor (some argue that all these attractors are really just specific instances of the singularity attractor).
  - gumby 3y ago
    It's a nice hard problem with lots of juicy subproblems that you can work on even through the central problem (materials science) is nowhere near being solvable.
  - martincmartin 3y ago
    John McCarthy was Moravec's PhD advisor.
- zorked 3y ago
  This is considerably more interesting that the original link...
- effed3 3y ago
  I wonder what will happen to the others planets, on a long scale... in a dynamical (chaotic) system stability is not granted, probably a bunch of asteroids-tools are needed to correct the deviation of all others planets form a desired configuration.
- cbsks 3y ago
  The sci-fi book practically writes itself. A wealthy entrepreneur puts an asteroid in motion to move mars and sets up a long term foundation to keep it operational for the next 40,000 years. In conjunction with the orbital adjustment, terraforming begins and the first enclosed permanent settlements are founded. After the orbital changes are complete, the new planet is open for human development and is renamed from Mars to Musk, after its visionary founder.
  - coldtea 3y ago
    Of course things go horribly wrong, and Mars crashes into earth. The moral of the story being if you don't have ultra-superior technology and experience doing the same thing outside of your own solar system and checking the results to adjust your procedures, then nudging things and seeing what happens at planetary scale is playing with fire.
  - justinjlynn 3y ago
    Is there any better embodiment of entrepreneurial capitalism than stealthily appropriating an entire planet, privatising it, and then naming it after one's self? ... I'd be hard pressed to think of one.
  - OneDonOne 3y ago
    I thought it was the short stories "Sunken Gardens" and "Cicada Queen" by Bruce Sterling from his Shaper/Mechanist universe. Oh well.
WalterBright 3y ago
Maybe an easier job would be to cool Venus by blocking sunlight from reaching it. Then, terraform it.
- chimpanzee 3y ago
  But me big man. Me move mars.
- virtue3 3y ago
  And then you get a world bathed in eternal darkness until you control it's greenhouse gas atmosphere? I think it would be easier to just limit greenhouse gas emissions on earth. Your point works pretty well considering that Venus has a a dense atmosphere unlike Mars.
  - kleer001 3y ago
    It certainly would. However, these are centuries long plans. A path along which the local issues will be solved.
  - WalterBright 3y ago
    Just need to reduce the solar incidence, not eliminate it. The same technology could be used to reduce gw on the earth: 1. an orbiting sunshade 2. putting something in the atmosphere that makes it more reflective, like sulfur dioxide I wonder how big a sunshade would need to be to reduce temps by, say, one degree. A specific location could be shaded by putting the shade in geosynchronous orbit. To finance the sunshade, put a Starbucks or Coca-Cola logo on it.
    - bee_rider 3y ago
      Or a giant “Welcome to Disney’s World.”
      - Hikikomori 3y ago
        Since so many believe aliens are here already we might as well start advertising to them.
microtherion 3y ago
Maybe it's for the better that McCarthy passed away in 2011; if he were still alive, he might have gotten a grant from SpaceX to put his scheme into action.
- CyberDildonics 3y ago
  Does spaceX give out grants to programmers?
- xdavidliu 3y ago
  I think you mean "put his emacs lisp into action"

behnamoh 3y ago

[flagged]

vjust 3y ago
All Lisp related stories, especially those that refer to the creator of Lisp, get automagically upvoted.
AnimalMuppet 3y ago
Because some people find it interesting. Same as everything else on HN's front page.

Bostonian 3y ago

I guess if you want a library for linear algebra operations in Lisp, you just write them yourself. From McCarthy's collection: ;;; multiplying a matrix by a column vector (defun mvmult (matrix vector) (list (scap (nth 0 matrix) vector) (scap (nth 1 matrix) vector))) ;;; sum of two vectors (defun vplus (vec1 vec2) (list (+ (nth 0 vec1) (nth 0 vec2)) (+ (nth 1 vec1) (nth 1 vec2)))) ;;; difference of two vectors (defun vminus (vec1 vec2) (list (- (nth 0 vec1) (nth 0 vec2)) (- (nth 1 vec1) (nth 1 vec2)))) ;;; scalar product of two vectors (defun scap (vec1 vec2) (+ (* (nth 0 vec1) (nth 0 vec2)) (* (nth 1 vec1) (nth 1 vec2)))) ;;; product of scalar and vector (defun svmult (sca vec) (list (* sca (nth 0 vec)) (* sca (nth 1 vec)))) ;;; sum of a list of vectors (defun addup (veclist) (if (null veclist) zerovec (vplus (car veclist) (addup (cdr veclist))))) (defconst zerovec '(0 0) "zero vector with two components"1) ;;; length of a vector (defun length (x) (sqrt (+ (expt (nth 0 x) 2) (expt (nth 1 x) 2)))) (defconst Imatrix '((1.0 0.0) (0.0 1.0)) "unit 2x2 matrix") (defun smmult (sca matrix) (list (svmult sca (nth 0 matrix)) (svmult sca (nth 1 matrix)))) (defun mplus (mat1 mat2) (list (vplus (nth 0 mat1) (nth 0 mat2)) (vplus (nth 1 mat1) (nth 1 mat2)))) (defun mminus (mat1 mat2) (list (vminus (nth 0 mat1) (nth 0 mat2)) (vminus (nth 1 mat1) (nth 1 mat2)))) (defun mmult (mat1 mat2) (list (list (scap (nth 0 mat1) (col 0 mat1)) (scap (nth 0 mat1) (col 1 mat1))) (list (scap (nth 1 mat1) (col 0 mat1)) (scap (nth 1 mat1) (col 1 mat1))))) (defun multiplyup (matlist) (if (null matlist) Imatrix (mmult (car matlist) (multiplyup (car matlist) (multiplyup (cdr (matlist)))))))

BaculumMeumEst 3y ago
see also https://github.com/jb55/vrscript-samples/blob/master/vr.rkt https://github.com/jb55/vrscript-samples/blob/master/vr.rkt
zelphirkalt 3y ago
Of course one can do this and it might work as a stopgap solution and abstraction layer until something different comes along and I have done similar, but ultimately this will not be very efficient. It might be a better, albeit less beautiful, solution to use any low level language inplemented linear algebra bindings for the lisp at hand. Hopefully there existing one.

bitwize 3y ago

What's interesting to me is that the creator of Lisp found Emacs Lisp acceptable for practical general use. (Although as noted this file can be loaded verbatim into Common Lisp and work fine.)

Zambyte 3y ago
McCarthy did not invent Lisp with the expectation that it even could be used as a language for real computers. Steve Russell had to convince him that McCarthy's theoretical definition of Lisp would actually work by actually implementing the interpreter himself. I don't think McCarty would have been too snobbish in dialects, considering he wasn't expecting a practical language at all :D
- lispm 3y ago
  > McCarthy did not invent Lisp with the expectation that it even could be used as a language for real computers. He was expecting a practical language and was designing one. Lisp was from day zero a project to implement a real programming language for a real computer. Earlier he experimented with IPL and also list processing / functional programming in Fortran. The original plan was to implement a Lisp compiler. At first the Lisp code, which McCarthy was experimenting with, was manually translated to machine code. So before the first Lisp compiler or interpreter existed, he was experimenting with how to represent and make the code running on a computer. He then invented a Lisp interpreter in Lisp. Then came up the idea (-> Steve Russell) to use this EVAL as a base for an interpreter implementation, which was also implemented by manually translating the Lisp code to machine language. McCarthy at first thought that it was not possible to use this Lisp evaluator written in Lisp as a base, but Steve Russell implemented it. Around 1962 then a Lisp compiler followed. The paper by Herbert Stoyan describes the history of McCarthy's Lisp project: https://github.com/papers-we-love/papers-we-love/blob/main/comp_sci_fundamentals_and_history/early-lisp-history-1956-1959-herbert-stoyan-html-rendering.pdf https://github.com/papers-we-love/papers-we-love/blob/main/c... > considering he wasn't expecting a practical language at all :D He was expecting a practical language, since he was designing one and the team was implementing it. He designed data structures, core functions, evaluation, garbage collection as memory management, input and output, ... The language was to be used as a list processing language for research in the upcoming field of Artificial Intelligence: game play, natural language dialogs, symbolic maths (integration, ...), logic reasoning, computer vision, robotics, ... He wrote several design documents on the language and its implementation. There even is the Lisp I Programmer's Manual from March 1960: https://bitsavers.org/pdf/mit/rle_lisp/LISP_I_Programmers_Manual_Mar60.pdf https://bitsavers.org/pdf/mit/rle_lisp/LISP_I_Programmers_Ma... Lisp was initially developed for an IBM 704 computer and primitive list operations CAR (= FIRST, HEAD) and CDR (= REST, TAIL) were referencing machine architecture details of the IBM 704.

agnosticmantis 3y ago

Some may find it interesting that John McCarthy coined the term Artificial Intelligence and was called a/the father of AI before the deep learning folks took over. This AI referred to the symbolic flavor not the connectionist one. Nowadays (god-)fathers of AI are Geoff Hinton and Yann LeCun and others, but 20 years ago things were very different…

morelisp 3y ago
20 years ago symbolic reasoning was already called GOFAI and the hotness was Bayesian statistical reasoning. 40 years ago, maybe.
- agnosticmantis 3y ago
  I was a kid back then, so not really aware of the cutting edge research happening in those days, but here’s for example the description of Russel & Norvig’s “Artificial Intelligence: A Modern Approach (2nd edition, published 2003)”: “The long-anticipated revision of this best-selling book offers the most comprehensive, up-to-date introduction to the theory and practice of artificial intelligence. Intelligent Agents. Solving Problems by Searching. Informed Search Methods. Game Playing. Agents that Reason Logically. First-order Logic. Building a Knowledge Base. Inference in First-Order Logic. Logical Reasoning Systems. Practical Planning. Planning and Acting. Uncertainty. Probabilistic Reasoning Systems. Making Simple Decisions. Making Complex Decisions. Learning from Observations. Learning with Neural Networks. Reinforcement Learning. Knowledge in Learning. Agents that Communicate. Practical Communication in English. Perception. Robotics. For those interested in artificial intelligence.”
  - morelisp 3y ago
    By necessity, textbooks lag the actual work in most fields. Nonetheless the titular “modern approach” is the statistical reasoning (plus a heavy focus on search over inference).
fsckboy 3y ago
> This AI referred to the symbolic flavor not the connectionist one that's not a fair characterization at all. The title contains the term "Artificial Intelligience", and soon after item 3 in the proposal was "Neuron Nets". The word symbolic is not used at all, although the term Abstractions is used. http://www-formal.stanford.edu/jmc/history/dartmouth/dartmouth.html http://www-formal.stanford.edu/jmc/history/dartmouth/dartmou... A PROPOSAL FOR THE DARTMOUTH SUMMER RESEARCH PROJECT ON ARTIFICIAL INTELLIGENCE J. McCarthy, Dartmouth College M. L. Minsky, Harvard University N. Rochester, I.B.M. Corporation C.E. Shannon, Bell Telephone Laboratories August 31, 1955 We propose that a 2 month, 10 man study of artificial intelligence be carried out during the summer of 1956 at Dartmouth College in Hanover, New Hampshire. The study is to proceed on the basis of the conjecture that every aspect of learning or any other feature of intelligence can in principle be so precisely described that a machine can be made to simulate it. An attempt will be made to find how to make machines use language, form abstractions and concepts, solve kinds of problems now reserved for humans, and improve themselves. We think that a significant advance can be made in one or more of these problems if a carefully selected group of scientists work on it together for a summer. The following are some aspects of the artificial intelligence problem: 1 Automatic Computers If a machine can do a job, then an automatic calculator can be programmed to simulate the machine. The speeds and memory capacities of present computers may be insufficient to simulate many of the higher functions of the human brain, but the major obstacle is not lack of machine capacity, but our inability to write programs taking full advantage of what we have. 2. How Can a Computer be Programmed to Use a Language It may be speculated that a large part of human thought consists of manipulating words according to rules of reasoning and rules of conjecture. From this point of view, forming a generalization consists of admitting a new word and some rules whereby sentences containing it imply and are implied by others. This idea has never been very precisely formulated nor have examples been worked out. 3. Neuron Nets How can a set of (hypothetical) neurons be arranged so as to form concepts. Considerable theoretical and experimental work has been done on this problem by Uttley, Rashevsky and his group, Farley and Clark, Pitts and McCulloch, Minsky, Rochester and Holland, and others. Partial results have been obtained but the problem needs more theoretical work. 4. Theory of the Size of a Calculation If we are given a well-defined problem (one for which it is possible to test mechanically whether or not a proposed answer is a valid answer) one way of solving it is to try all possible answers in order. This method is inefficient, and to exclude it one must have some criterion for efficiency of calculation. Some consideration will show that to get a measure of the efficiency of a calculation it is necessary to have on hand a method of measuring the complexity of calculating devices which in turn can be done if one has a theory of the complexity of functions. Some partial results on this problem have been obtained by Shannon, and also by McCarthy. 5. Self-lmprovement Probably a truly intelligent machine will carry out activities which may best be described as self-improvement. Some schemes for doing this have been proposed and are worth further study. It seems likely that this question can be studied abstractly as well. 6. Abstractions A number of types of ``abstraction'' can be distinctly defined and several others less distinctly. A direct attempt to classify these and to describe machine methods of forming abstractions from sensory and other data would seem worthwhile. 7. Randomness and Creativity A fairly attractive and yet clearly incomplete conjecture is that the difference between creative thinking and unimaginative competent thinking lies in the injection of a some randomness. The randomness must be guided by intuition to be efficient. In other words, the educated guess or the hunch include controlled randomness in otherwise orderly thinking. In addition to the above collectively formulated problems for study, we have asked the individuals taking part to describe what they will work on. Statements by the four originators of the project are attached. ... the paper continues ...

aj7 3y ago

Ok, a warmer Mars is desirable. But is Mars, in earth’s orbit, but on the opposite side of the sun, really closer?

0xfae 3y ago
Closer in terms of what? Distance? delta-v to get there? Time to get there?
_jal 3y ago
> Ok, a warmer Mars is desirable. To humans.
- serf 3y ago
  yeah, well that is the typical comparison one would make as a human.. you are a human, right?
  - deleted 3y ago
    [deleted]
trwaw 3y ago
Without a magbetosphere it's pretty useless. It would just lose its atmosphere again within a few hundred years.
- bmitc 3y ago
  Agreed. It's the very definition of a dead planet, and there is even a high probability that it had life before Earth.
lmm 3y ago
In travel time, no. In energy cost, yes, but only if you're willing to wait a long time to get there. Also impossible to communicate with directly by radio.

mckn1ght 3y ago

I made a GitHub repo mirroring it: https://github.com/armcknight/john-mccarthy-numerical-facts https://github.com/armcknight/john-mccarthy-numerical-facts Also saw someone else just added it to one of theirs: https://github.com/bbarclay7/bb-emacs/blob/5858823bb033be113a4d98a969ff6923510ecc4e/lisp/facts.el https://github.com/bbarclay7/bb-emacs/blob/5858823bb033be113...

nxobject 3y ago

Now we know: John McCarthy used (x)emacs. Clearly an important revelation in the ongoing browser wars. /s (and not to minimize how genuinely interesting this is)

thsksbd 3y ago

Very cool, but I wonder why did he define foot as: (setq foot (* 0.3048 m)) And not (setq foot (* 12 inch)) It comes to the same thing, but inch is defined in metric as 2.54 cm and the foot is a derived unit of the inch. But this way it clearly spells out the dependency. Im not criticizing, it was his library for his use, I'm just wondering if there is there a deeper meaning beyond "God enough"?

jwhitlark 3y ago
Heh, the creator of Lisp probably was "God enough" to redef constants as he saw fit.
melling 3y ago
He wanted to work in meters? Closer to his final result? (setq km (* m 1000.0)) (setq cm (* m 0.01)) (setq foot (* 0.3048 m)) (setq ft (* 0.3048 m)) (setq mile (* 5280 foot))
- traes 3y ago
  The very snippet you gave there is a counterexample to your argument. He defines miles in terms of feet (which is in turn defined by meters) allowing him to use commonly known conversion factors as a sanity check, while still keeping all values in meters. If he had used his already present definition of an inch as 0.0254 meters to define feet, he could have compounded this even further. The true answer is almost certainly that he simply did whatever came to mind first, and didn't think of defining feet in terms of inches because he hadn't defined inches yet.
  - thsksbd 3y ago
    I mean the legal definition of the inch is 25.4 mm. All other imperial length units are derived from the inch. Furthermore, there are more than one definition of the inch. If he worked on astronomical data from the 19th century UK, all these units would have to be changed. By tying the foot to the inch he'd only have to redefine the inch to the old British inch.

dkbrk 3y ago

This might come in handy but it's much inferior to the frink units file [0] which is much more complete, more rigorous, and includes dimensions. [0]: https://frinklang.org/frinkdata/units.txt https://frinklang.org/frinkdata/units.txt

bsza 3y ago
That rant about the hertz is HN top material in and of itself.
Archit3ch 3y ago
> I think the candela is a scam
mock-possum 3y ago
Oh my god this is incredible

Exuma 3y ago

One thing I always wonder is how people throughout history, on famous historic codebases etc, can indent things.... 90% the way, and then out of dozes of things correct there will be 3 things that are painfully off. Man, just indent them all the way if youre going to do it halfway Ive seen this in dennis richie code, doom code, etc Am i the only person who sees these things stand out like a sore thumb? It would drive me mad. They either all have to be not aligned, or aligned, but not 90%

Exuma 3y ago

pony := 1 floz jigger := 1.5 floz

CyberDildonics 3y ago

Are equations being renamed to 'numerical facts' now?

kagevf 3y ago

So, I know that elisp has historically lacked lexical scope, so setting variables without a prefix has the potential for name clashes since even a variable setq'd into existence inside a defun will be added to the global namespace. I did an experiment to double check it's still true in a recent-ish emacs: (defun my-fun () (setq test-123-456 'this-is-a-test)) (my-fun) test-123-456 => this-is-a-test There is some information in the info file under elisp about lexical binding, but you can just use let to keep variables in a lexical scope. (defun my-other-fun () (let ((test-789 'this-is-another-test)) test-789)) (my-other-fun) test-789 => *** Eval error *** Symbol’s value as variable is void: test-789

shric 3y ago

Some of the constants have changed over the years. > (setq avogadro 6.0221367e23) ; Avogadro number This is now standardized to exactly 6.02214076e23