Showing posts with label science. Show all posts
Showing posts with label science. Show all posts

Thursday, March 26, 2015

Despre religie, stiinta si scoala

S-a discutat mult in ultimele saptamani pe tema orelor de religie in scoli. Desi am ajuns tarziu la masa discutiilor, o sa abordez si eu aceasta problema, dar dintr-un unghi putin diferit. In contextul acestei discutii am aflat ca acum cativa ani Ministerul Educatiei a scos teoria evolutiei a lui Darwin din programa scolara la presiunile BOR. Ba mai mult, adeptii bisericii vorbesc de o teorie alternativa, creationismul, si spun ca eventual ar trebui studiate amandoua in paralel, sau lasa optiunea profesorului ce teorie sa prezinte la clasa. Dar nu toate teoriile sunt nascute egale si tocmai despre asta o sa vorbesc mai departe. Epistemologia esta ramura filosofiei care studiaza natura cunoasterii stiintifice, iar una din cele mai mari contributii pe aceasta tema este cartea Objective Knowledge a lui Karl Popper. Ca mai toate cartile de filosofie, e scrisa intr-un limbaj arid, dar ideile principale sunt pana la urma simple si de bun simt (imi amintesc ca discutam acum cativa ani cu cineva despre aceasta carte si am ajuns la concluzia ca ar trebui sa fie lectura obligatorie pentru oricine pretinde ca are de-a face cu stiinta).

Pe scurt Popper sustine urmatoarele:
- cunoasterea umana e formata exclusiv din teorii; de exemplu daca acum e noapte, faptul ca eu ma astept ca in cateva ore sa rasara soarele din nou e o teorie, s-ar putea sa se intample asa sau nu;
- nicio teorie despre lumea din jur nu poate fi demonstrata astfel incat sa fim siguri ca e adevarata. Practic nu putem fi siguri de nimic pe lumea asta, nici macar de moarte si taxe :) 
- o teorie poate fi insa infirmata prin observarea unor fapte care o contrazic; de exemplu, daca teoria mea e ca soarele rasare in fiecare zi la 6 si maine soarele rasare la 7 atunci teoria mea va fi infirmata;
- practic natura cunoasterii umane e negativa, nu pozitiva; fiecare din noi vine cu tot felul de teorii, iar multe dintre ele sunt aruncate la gunoi pe masura ce realitatea le contrazice; sau rafinate, cum este cazul cu teoria lui Einstein despre gravitatie care de fapt o imbunatateste pe cea a lui Newton pe aceeasi tema (care, de exemplu, prezicea gresit orbita planetei Mercur); cred ca chiar acest exemplu cu teoria gravitatiei a fost sursa de inspiratie pentru aceasta carte a lui Popper;
- o teorie stiintifica e o teorie pe baza careia putem face predictii pe care le putem verifica. Aici se despart apele de fapt intre stiinta si religie, magie, filosofie si orice altceva care emite pareri despre lumea asta. Ca sa nu ziceti ca am ceva cu religia, o dau un exemplu din filosofie. Exista un curent filosofic care sustine ca tot ce ni se intampla noua e de fapt un vis. Oamenii astia nu pot fi combatuti cu nimic, daca il ciupesti de mana si il doare el o sa spuna ca de fapt viseaza ca il doare si tot asa. Din moment ce teoria asta nu face nicio predictie care poate fi infirmata despre ce s-ar putea intampla maine ea nu poate fi combatuta.

Asta e de fapt marea problema cu ce se intampla in scoala romaneasca. Acum, fiecare e liber sa creada ce vrea si in ce vrea, dar atunci cand vorbim despre materiile care tin de stiinte e aberant sa punem pe picior de egalitate o teorie stiintifica, cum e cea a evolutiei, cu una pe care nu o putem combate in niciun fel, caci sustine ca orice s-ar intampla maine e vointa divinitatii.

Tuesday, February 17, 2015

What If Schrödinger's Cat Meows?

While playing with my cat last night it hit me this question: what would happen if the cat in Schrödinger's thought experiment was meowing? You would know if the cat is dead or alive because the meowing would stop. Or maybe you will be in the same superposition with the cat inside the box and you will both hear the meowing and not hear it. Well, technically hearing the meowing is observing that system, so the assumptions of the experiment are not met. But the real question is how well can you isolate such a complex system (you know that cats are complex animals, they can love and hate you :)) from the environment in order to do such an experiment like the one Schrödinger proposed? I googled this and I found a similar question on a physics forum here. It turns out that if a system interacts with its environment (and we are talking not only about meowing, think about gravity influences as the weight of a cat is significant by quantum mechanics standards) then the quantum superposition collapses to only one of the possible options (the term used in physics is quantum decoherence) and you don't have that limbo of a cat that is both dead and alive anymore.
This is the nice part of thought experiments: you don't need to hurt anybody, you just need to think really hard a and you will eventually find your answer :)

P.S. I have to remember to write on how I found out that communism is bullshit via a thought experiment years ago. Remember how many lives were destroyed for this idea, only to learn it the hard way that communism is crap. And some still believe in it...

Friday, September 23, 2011

Caught speeding?

Apparently, not only that God plays dices (in the game called quantum mechanics), but he is also speeding. In an experiment performed at CERN it appears that neutrinos travel at a speed greater that the speed of light which is the theoretical ultimate speed limit postulated by Einstein in his relativity theory. The results are still up for review, the researchers say they want to eliminate every possible chance that they made a measurement or design error and would be glad to see their experiment replicated by another team, but I can't stop thinking what the venerable Einstein would think about this?

If this experiment turns out to be right, we have to re-write all our theories on physics. Again! So should I stop trying to understand the current ones? :)

More details on this story here.

Wednesday, April 27, 2011

Autism - what lies beneath

I first heard about autism in a computer science class, Computer Processing of Pictorial Information, that I took at UMD. It's true that the professor, Yiannis Aloimonos, was quite unconventional and was telling us lots of stories about human and computer vision, and left us to decipher the equations used there by ourselves. One of his main ideas was that in order to make progress in computer vision was to understand as much as possible how the human brain processes the visual stimulus that results in human vision. But apart from recommending us books on human vision research he told us about a book of a different kind: clinical tales of a neurologist (The Man Who Mistook His Wife For A Hat). In this book Oliver Sacks describes various cases of conditions or accidents that lead to an abnormal functioning of the brain and how people cope in these situations. One of the chapters in this book is about autism. This is a born condition that affects some children and which impairs social interaction and communication (a less severe form is the Asperger syndrome). But a good number of these people show some remarkable abilities: superior skills in perception (e.g. the ability to draw very accurate texture details), attention and computing (e.g. the ability to tell in an instant is a fairly big number is prime or not). This lead to a theory that somehow there is a trade-off in our brain: the computing power there is sufficient to be able to do instant computation of prime numbers but most of the time is shut down and the brain is wired for things much more useful to us like the ability to communicate and interact socially with other people.
Now I'm sure you'll have a different view on some piece of news like this one: A twelve year old rewrites Einstein's theory of relativity.

Sunday, February 27, 2011

AI-MAS Winter Olympics

On last Sunday I went to the second day of AI-MAS Winter Olympics conference that took place at the Polytechnic University of Bucharest. The main event on this day was a presentation of the machine learning algorithm that it used for implementing Priority Inbox feature in GMail. They basically use a neural network standard algorithm, but the challenge is keeping a separate model (which might have additional user specific features which are instantiated dynamically from some templates) for each particular user and training it as you also manually sort your email. The other issue is of course scalability and processing in real time of data (for example the algorithm takes into account even the time spent reading a particular message to determine if the user really read it, or just opened it to be marked as read). Apart from the presentations there were on display projects done by students. The one I liked most was the Swim Green project done by a team from Babes-Bolyai University. It was a boat-robot which could navigate based on visual input and also pick-up plastic pieces floating on the water. The goal was to propose an automatic clean-up mechanism that could be used on lakes for example. Overall it was a very nice experience and of course I'm glad these kind of things start happening in Romanian universities.

Saturday, December 19, 2009

The missing link

In a top of scientific discoveries of 2009 the discovery of a human-like fossil was name the science breakthrough of the year. This is a long debate and one of the arguments of non-believers in the theory of evolution: the fact that there are no species between monkeys and humans and the gap between them is too big to be explained by evolution. The scientists were looking for years for this type of fossil and it seems the finally found it: a creature that looks like a monkey but has some characteristics that indicates a biped walking. Unfortunately the evidence of talking cannot be seen in a fossil, so we will still debate for some time about where do we come from.

Monday, September 21, 2009

Space garbage

In the last 50 years the space exploration changed our lives: think only about GPS and satellite communications. But what happens with the satellites that are no longer in use? Some of them (the bigger ones) are driven back towards Earth and they burn in the atmosphere. But most of them are just left orbiting around the Earth. Thus the new place where garbage accumulates is in the space around our planet. This is more and more a concern because this kind of garbage can hit at any time a functional satellite or the ISS producing significant damage as satellites are designed to be as lite as possible, not resistant at impact with other objects. So now DARPA started to investigate ways to remove this garbage. Some more details here.

Wednesday, September 10, 2008

The black hole in their heads

So the new Cern collider will aim recreate conditions from the times closed to Big Bang and possibly even black holes and that made many people worried that the end of the world might come with this experiment. The Conservator Party from Romania even sent an open letter to some European institutions to stop the experiment :) The good news is that if a black hole is indeed produced they would not even feel when they will get past its horizon (the line that once passed you cannot escape the gravity of the the black hole). So we will not see them anymore!

Thursday, March 27, 2008

Einstein could be refuted

I read an interesting article in The Economist about some mismatches discovered between the predictions of the general relativity theory and some actual measurements. These mismatches were found a couple of times when various space missions used planetary gravity for acceleration (this is a cheap method to accelerate a space probe by swinging it around a planet, instead of installing powerful engines that also require a lot of fuel). The researchers are still checking the flight data of the various space probes to make sure there is no other explanation for this deviation, but this could become a serious flaw in the general relativity theory. Who wants to fix it? :)

Friday, March 14, 2008

Jules Verne goes to space

After more than a hundred years of wild imagination Jules Verne finally made it to space, in the form of an ATV, which is not an all terrain vehicle, but an automated transfer vehicle which can attach itself to the International Space Station without any human driving. This first ATV is called Jules Verne after the famous French science fiction writer. This is one big step in the European space program, showing some commitment into developing more and more advanced space technology. See details about first ATV mission here.

Thursday, November 29, 2007

Making solar energy cheaper than coal energy

Google announced recently they will invest/donate a large amount of money into research on how to make the generation of solar energy cheaper than the one generated by burning coal. They also plan to hire researchers in a newly created department at Google to study this problem. More here and in an interview here.

Friday, April 07, 2006

The fish doesn't think...

Busy period for me lately - I changed my job among other stuff - so I didn't blog for a while. I just stopped by to tell you that it's official now, according to the latest findings we evloved from fish.

...the fish knows everything.

Wednesday, October 12, 2005

Universe in a nutshell

I finished reading "The Universe in a Nutshell" by Stephen Hawking. He describes the current search in physics for a universal theory that would describe the universe, and reconcile the relativity theory with quantum mechanics. I knew some of the theories explained there from other books of science popularization, but this one is very well written and entertaining. There is also one chapter not related to physics theories, but to the potential evolution of the human society.
I think this is the weaker part of the book, as I don't think we will be in competition with any artificial intelligence any time soon, if ever. Nice to see the reference he mades to Popper and his epistemology. I think everyone doing science should be aware of Popper's theory and the limits of our knowledge.

Friday, March 18, 2005

I don't read only books

Over the last three days I read three interesting articles pointed out by some friends:
- one about an autistic boy that wrote some poems describing what he feels;
- the second one is about new research that shows the importance of the X chromosome in humans;

The last article is about how to design a good interface of a search portal; it was written two years ago, but the ideas expressed there are very actual. I think as software become more and more complex designing a usable interface will more important than ever. Another online reference about designing good user interfaces in your software is here.

Thursday, February 24, 2005

Autistic people

I read an extraordinary article in Guardian (via slashdot.org) about one autistic person that also can explain up to some point what happens to him. I got interested in this area after a professor of mine (Yiannis Aloimonos) sugested us to read about autistic people as part of a computer vision class. It seems that we all have similar capabilities (like doing complex arithmetics mentally), but we just can't access this layer in our brains.