0:00:03.646,0:00:06.612
So, this is my grandfather,

0:00:06.612,0:00:08.113
Salman Schocken,

0:00:08.113,0:00:12.550
who was born into a poor and uneducated family

0:00:12.550,0:00:15.987
with six children to feed,

0:00:15.987,0:00:19.683
and when he was 14 years old, he was forced to

0:00:19.683,0:00:23.643
drop out of school in order to help put bread on the table.

0:00:23.643,0:00:27.063
He never went back to school.

0:00:27.063,0:00:31.210
Instead, he went on to build a glittering empire

0:00:31.210,0:00:33.318
of department stores.

0:00:33.318,0:00:36.571
Salman was the consummate perfectionist,

0:00:36.571,0:00:39.135
and every one of his stores was a jewel

0:00:39.135,0:00:41.064
of Bauhaus architecture.

0:00:41.064,0:00:44.254
He was also the ultimate self-learner,

0:00:44.254,0:00:47.157
and like everything else, he did it in grand style.

0:00:47.157,0:00:49.845
He surrounded himself with an entourage

0:00:49.845,0:00:53.232
of young, unknown scholars like Martin Buber

0:00:53.232,0:00:56.371
and Shai Agnon and Franz Kafka,

0:00:56.371,0:00:59.296
and he paid each one of them a monthly salary

0:00:59.296,0:01:02.347
so that they could write in peace.

0:01:02.347,0:01:07.284
And yet, in the late '30s, Salman saw what's coming.

0:01:07.284,0:01:10.598
He fled Germany, together with his family,

0:01:10.598,0:01:12.687
leaving everything else behind.

0:01:12.687,0:01:15.897
His department stores confiscated,

0:01:15.897,0:01:18.986
he spent the rest of his life in a relentless pursuit

0:01:18.986,0:01:21.455
of art and culture.

0:01:21.455,0:01:23.394
This high school dropout

0:01:23.394,0:01:25.674
died at the age of 82,

0:01:25.674,0:01:29.803
a formidable intellectual, cofounder and first CEO

0:01:29.803,0:01:31.948
of the Hebrew University of Jerusalem,

0:01:31.948,0:01:33.712
and founder of Schocken Books,

0:01:33.712,0:01:37.083
an acclaimed imprint that was later acquired

0:01:37.083,0:01:38.753
by Random House.

0:01:38.753,0:01:42.729
Such is the power of self-study.

0:01:42.729,0:01:45.245
And these are my parents.

0:01:45.245,0:01:49.292
They too did not enjoy the privilege of college education.

0:01:49.292,0:01:53.263
They were too busy building a family and a country.

0:01:53.263,0:01:57.291
And yet, just like Salman, they were lifelong,

0:01:57.291,0:02:01.049
tenacious self-learners, and our home was stacked

0:02:01.049,0:02:05.212
with thousands of books, records and artwork.

0:02:05.212,0:02:07.608
I remember quite vividly my father telling me

0:02:07.608,0:02:12.440
that when everyone in the neighborhood will have a TV set,

0:02:12.440,0:02:17.058
then we'll buy a normal F.M. radio. (Laughter)

0:02:17.058,0:02:20.087
And that's me,

0:02:20.087,0:02:21.811
I was going to say holding my first abacus,

0:02:21.811,0:02:24.822
but actually holding what my father would consider

0:02:24.822,0:02:27.774
an ample substitute to an iPad. (Laughter)

0:02:27.774,0:02:31.436
So one thing that I took from home is this notion

0:02:31.436,0:02:34.277
that educators don't necessarily have to teach.

0:02:34.277,0:02:37.506
Instead, they can provide an environment and resources

0:02:37.506,0:02:42.654
that tease out your natural ability to learn on your own.

0:02:42.654,0:02:46.748
Self-study, self-exploration, self-empowerment:

0:02:46.748,0:02:50.068
these are the virtues of a great education.

0:02:50.068,0:02:54.263
So I'd like to share with you a story about a self-study,

0:02:54.263,0:02:56.817
self-empowering computer science course

0:02:56.817,0:03:01.003
that I built, together with my brilliant colleague Noam Nisan.

0:03:01.003,0:03:03.760
As you can see from the pictures, both Noam and I

0:03:03.760,0:03:07.178
had an early fascination with first principles,

0:03:07.178,0:03:08.700
and over the years, as our knowledge of

0:03:08.700,0:03:12.275
science and technology became more sophisticated,

0:03:12.275,0:03:15.471
this early awe with the basics

0:03:15.471,0:03:17.571
has only intensified.

0:03:17.571,0:03:21.270
So it's not surprising that, about 12 years ago, when

0:03:21.270,0:03:24.752
Noam and I were already computer science professors,

0:03:24.752,0:03:28.504
we were equally frustrated by the same phenomenon.

0:03:28.504,0:03:31.322
As computers became increasingly more complex,

0:03:31.322,0:03:34.526
our students were losing the forest for the trees,

0:03:34.526,0:03:37.613
and indeed, it is impossible to connect

0:03:37.613,0:03:40.255
with the soul of the machine if you interact

0:03:40.255,0:03:43.664
with a black box P.C. or a Mac which is shrouded

0:03:43.664,0:03:47.040
by numerous layers of closed, proprietary software.

0:03:47.040,0:03:50.730
So Noam and I had this insight that if we want our students

0:03:50.730,0:03:52.749
to understand how computers work,

0:03:52.749,0:03:55.837
and understand it in the marrow of their bones,

0:03:55.837,0:03:57.398
then perhaps the best way to go about it

0:03:57.398,0:04:01.992
is to have them build a complete, working,

0:04:01.992,0:04:05.704
general-purpose, useful computer, hardware and software,

0:04:05.704,0:04:09.234
from the ground up, from first principles.

0:04:09.234,0:04:13.442
Now, we had to start somewhere, and so Noam and I

0:04:13.442,0:04:16.932
decided to base our cathedral, so to speak,

0:04:16.932,0:04:20.071
on the simplest possible building block,

0:04:20.071,0:04:22.872
which is something called NAND.

0:04:22.872,0:04:26.810
It is nothing more than a trivial logic gate

0:04:26.810,0:04:29.848
with four input-output states.

0:04:29.848,0:04:32.514
So we now start this journey by telling our students

0:04:32.514,0:04:34.582
that God gave us NAND — (Laughter) —

0:04:34.582,0:04:38.567
and told us to build a computer, and when we asked how,

0:04:38.567,0:04:41.751
God said, "One step at a time."

0:04:41.751,0:04:44.844
And then, following this advice, we start

0:04:44.844,0:04:47.803
with this lowly, humble NAND gate,

0:04:47.803,0:04:49.743
and we walk our students through an elaborate sequence

0:04:49.743,0:04:53.480
of projects in which they gradually build a chip set,

0:04:53.480,0:04:57.592
a hardware platform, an assembler, a virtual machine,

0:04:57.592,0:05:01.169
a basic operating system and a compiler

0:05:01.169,0:05:07.358
for a simple, Java-like language that we call "JACK."

0:05:07.358,0:05:09.906
The students celebrate the end of this tour de force

0:05:09.906,0:05:12.740
by using JACK to write all sorts of cool games

0:05:12.740,0:05:15.732
like Pong, Snake and Tetris.

0:05:15.732,0:05:19.347
You can imagine the tremendous joy of playing

0:05:19.347,0:05:22.371
with a Tetris game that you wrote in JACK

0:05:22.371,0:05:25.161
and then compiled into machine language in a compiler

0:05:25.161,0:05:27.569
that you wrote also, and then seeing the result

0:05:27.569,0:05:30.452
running on a machine that you built starting

0:05:30.452,0:05:33.736
with nothing more than a few thousand NAND gates.

0:05:33.736,0:05:36.926
It's a tremendous personal triumph of going

0:05:36.926,0:05:41.651
from first principles all the way to a fantastically complex

0:05:41.651,0:05:44.002
and useful system.

0:05:44.002,0:05:48.399
Noam and I worked five years to facilitate

0:05:48.399,0:05:51.607
this ascent and to create the tools and infrastructure

0:05:51.607,0:05:54.780
that will enable students to build it in one semester.

0:05:54.780,0:05:58.819
And this is the great team that helped us make it happen.

0:05:58.819,0:06:03.066
The trick was to decompose the computer's construction

0:06:03.066,0:06:06.020
into numerous stand-alone modules,

0:06:06.020,0:06:09.920
each of which could be individually specified,

0:06:09.920,0:06:15.155
built and unit-tested in isolation from the rest of the project.

0:06:15.155,0:06:18.144
And from day one, Noam and I decided to put

0:06:18.144,0:06:21.680
all these building blocks freely available in open source

0:06:21.680,0:06:23.160
on the Web.

0:06:23.160,0:06:27.631
So chip specifications, APIs, project descriptions,

0:06:27.631,0:06:31.535
software tools, hardware simulators, CPU emulators,

0:06:31.535,0:06:35.237
stacks of hundreds of slides, lectures --

0:06:35.237,0:06:37.464
we laid out everything on the Web

0:06:37.464,0:06:40.491
and invited the world to come over,

0:06:40.491,0:06:42.027
take whatever they need,

0:06:42.027,0:06:44.417
and do whatever they want with it.

0:06:44.417,0:06:48.316
And then something fascinating happened.

0:06:48.316,0:06:49.899
The world came.

0:06:49.899,0:06:53.057
And in short order, thousands of people

0:06:53.057,0:06:54.601
were building our machine.

0:06:54.601,0:06:58.525
And NAND2Tetris became one of the first

0:06:58.525,0:07:01.755
massive, open, online courses,

0:07:01.755,0:07:04.499
although seven years ago we had no idea that what

0:07:04.499,0:07:06.660
we were doing is called MOOCs.

0:07:06.660,0:07:10.518
We just observed how self-organized courses

0:07:10.518,0:07:13.600
were kind of spontaneously spawning

0:07:13.600,0:07:14.983
out of our materials.

0:07:14.983,0:07:18.074
For example, Pramode C.E.,

0:07:18.074,0:07:19.983
an engineer from Kerala, India,

0:07:19.983,0:07:21.792
has organized groups of self-learners

0:07:21.792,0:07:24.836
who build our computer under his good guidance.

0:07:24.836,0:07:27.858
And Parag Shah, another engineer, from Mumbai,

0:07:27.858,0:07:30.703
has unbundled our projects into smaller,

0:07:30.703,0:07:32.725
more manageable bites that he now serves

0:07:32.725,0:07:36.527
in his pioneering do-it-yourself computer science program.

0:07:36.527,0:07:39.938
The people who are attracted to these courses

0:07:39.938,0:07:42.358
typically have a hacker mentality.

0:07:42.358,0:07:44.463
They want to figure out how things work,

0:07:44.463,0:07:46.223
and they want to do it in groups,

0:07:46.223,0:07:49.034
like this hackers club in Washington, D.C.,

0:07:49.034,0:07:52.699
that uses our materials to offer community courses.

0:07:52.699,0:07:55.645
And because these materials are widely available

0:07:55.645,0:07:58.339
and open-source, different people take them

0:07:58.339,0:08:01.282
to very different and unpredictable directions.

0:08:01.282,0:08:04.195
For example, Yu Fangmin, from Guangzhou,

0:08:04.195,0:08:07.041
has used FPGA technology

0:08:07.041,0:08:10.766
to build our computer and show others how to do the same

0:08:10.766,0:08:14.129
using a video clip, and Ben Craddock developed

0:08:14.129,0:08:17.730
a very nice computer game that unfolds

0:08:17.730,0:08:22.699
inside our CPU architecture, which is quite a complex

0:08:22.699,0:08:25.184
3D maze that Ben developed

0:08:25.184,0:08:29.092
using the Minecraft 3D simulator engine.

0:08:29.092,0:08:32.110
The Minecraft community went bananas over this project,

0:08:32.110,0:08:35.494
and Ben became an instant media celebrity.

0:08:35.494,0:08:38.396
And indeed, for quite a few people,

0:08:38.396,0:08:42.473
taking this NAND2Tetris pilgrimage, if you will,

0:08:42.473,0:08:45.185
has turned into a life-changing experience.

0:08:45.185,0:08:48.374
For example, take Dan Rounds, who is a music

0:08:48.374,0:08:51.143
and math major from East Lansing, Michigan.

0:08:51.143,0:08:54.587
A few weeks ago, Dan posted a victorious post

0:08:54.587,0:08:57.207
on our website, and I'd like to read it to you.

0:08:57.207,0:09:00.665
So here's what Dan said.

0:09:00.665,0:09:03.477
"I did the coursework because understanding computers

0:09:03.477,0:09:06.823
is important to me, just like literacy and numeracy,

0:09:06.823,0:09:09.840
and I made it through. I never worked harder on anything,

0:09:09.840,0:09:12.549
never been challenged to this degree.

0:09:12.549,0:09:14.936
But given what I now feel capable of doing,

0:09:14.936,0:09:17.094
I would certainly do it again.

0:09:17.094,0:09:19.344
To anyone considering NAND2Tetris,

0:09:19.344,0:09:23.090
it's a tough journey, but you'll be profoundly changed."

0:09:23.090,0:09:27.990
So Dan demonstrates the many self-learners

0:09:27.990,0:09:32.636
who take this course off the Web, on their own traction,

0:09:32.636,0:09:37.225
on their own initiative, and it's quite amazing because

0:09:37.225,0:09:41.812
these people cannot care less about

0:09:41.812,0:09:43.054
grades.

0:09:43.054,0:09:46.959
They are doing it because of one motivation only.

0:09:46.959,0:09:50.445
They have a tremendous passion to learn.

0:09:50.445,0:09:52.369
And with that in mind,

0:09:52.369,0:09:56.973
I'd like to say a few words about traditional college grading.

0:09:56.973,0:09:59.333
I'm sick of it.

0:09:59.333,0:10:00.766
We are obsessed with grades

0:10:00.766,0:10:02.632
because we are obsessed with data,

0:10:02.632,0:10:07.219
and yet grading takes away all the fun from failing,

0:10:07.219,0:10:09.695
and a huge part of education

0:10:09.695,0:10:11.286
is about failing.

0:10:11.286,0:10:13.761
Courage, according to Churchill,

0:10:13.761,0:10:16.707
is the ability to go from one defeat to another

0:10:16.707,0:10:19.321
without losing enthusiasm. (Laughter)

0:10:19.321,0:10:23.151
And [Joyce] said that mistakes

0:10:23.151,0:10:24.620
are the portals of discovery.

0:10:24.620,0:10:27.966
And yet we don't tolerate mistakes,

0:10:27.966,0:10:29.275
and we worship grades.

0:10:29.275,0:10:33.063
So we collect your B pluses and your A minuses

0:10:33.063,0:10:35.900
and we aggregate them into a number like 3.4,

0:10:35.900,0:10:37.811
which is stamped on your forehead

0:10:37.811,0:10:40.254
and sums up who you are.

0:10:40.254,0:10:43.537
Well, in my opinion, we went too far with this nonsense,

0:10:43.537,0:10:46.218
and grading became degrading.

0:10:46.218,0:10:51.119
So with that, I'd like to say a few words about upgrading,

0:10:51.119,0:10:55.544
and share with you a glimpse from my current project,

0:10:55.544,0:10:57.574
which is different from the previous one,

0:10:57.574,0:10:59.588
but it shares exactly the same characteristics

0:10:59.588,0:11:03.415
of self-learning, learning by doing,

0:11:03.415,0:11:06.190
self-exploration and community-building,

0:11:06.190,0:11:12.050
and this project deals with K-12 math education,

0:11:12.050,0:11:13.954
beginning with early age math,

0:11:13.954,0:11:18.447
and we do it on tablets because we believe that

0:11:18.447,0:11:22.852
math, like anything else, should be taught hands on.

0:11:22.852,0:11:26.007
So here's what we do. Basically, we developed

0:11:26.007,0:11:29.765
numerous mobile apps, every one of them explaining

0:11:29.765,0:11:31.262
a particular concept in math.

0:11:31.262,0:11:34.703
So for example, let's take area.

0:11:34.703,0:11:37.175
When you deal with a concept like area --

0:11:37.175,0:11:42.419
well, we also provide a set of tools that the child

0:11:42.419,0:11:45.050
is invited to experiment with in order to learn.

0:11:45.050,0:11:49.003
So if area is what interests us, then one thing

0:11:49.003,0:11:53.141
which is natural to do is to tile the area

0:11:53.141,0:11:56.791
of this particular shape and simply count

0:11:56.791,0:12:00.654
how many tiles it takes to cover it completely.

0:12:00.654,0:12:03.136
And this little exercise here gives you a first

0:12:03.136,0:12:06.565
good insight of the notion of area.

0:12:06.565,0:12:09.355
Moving along, what about the area of this figure?

0:12:09.355,0:12:14.012
Well, if you try to tile it, it doesn't work too well, does it.

0:12:14.012,0:12:16.316
So instead, you can experiment

0:12:16.316,0:12:18.996
with these different tools here by some process

0:12:18.996,0:12:21.035
of guided trial and error,

0:12:21.035,0:12:23.873
and at some point you will discover that one thing

0:12:23.873,0:12:26.961
that you can do among several legitimate transformations

0:12:26.961,0:12:29.792
is the following one. You can cut the figure,

0:12:29.792,0:12:33.408
you can rearrange the parts, you can glue them

0:12:33.408,0:12:36.525
and then proceed to tile just like we did before.

0:12:36.525,0:12:41.800
(Applause)

0:12:41.800,0:12:44.523
Now this particular transformation

0:12:44.523,0:12:48.507
did not change the area of the original figure,

0:12:48.507,0:12:50.694
so a six-year-old who plays with this

0:12:50.694,0:12:53.578
has just discovered a clever algorithm

0:12:53.578,0:12:57.618
to compute the area of any given parallelogram.

0:12:57.618,0:12:59.474
We don't replace teachers, by the way.

0:12:59.474,0:13:02.603
We believe that teachers should be empowered, not replaced.

0:13:02.603,0:13:05.898
Moving along, what about the area of a triangle?

0:13:05.898,0:13:08.693
So after some guided trial and error,

0:13:08.693,0:13:12.628
the child will discover, with or without help,

0:13:12.628,0:13:16.486
that he or she can duplicate the original figure

0:13:16.486,0:13:19.894
and then take the result, transpose it,

0:13:19.894,0:13:23.642
glue it to the original and then proceed [with] what we did before:

0:13:23.642,0:13:31.370
cut, rearrange, paste — oops— paste and glue,

0:13:31.370,0:13:32.966
and tile.

0:13:32.966,0:13:36.793
Now this transformation has doubled the area

0:13:36.793,0:13:40.643
of the original figure, and therefore we have just learned

0:13:40.643,0:13:44.409
that the area of the triangle equals the area of this rectangle

0:13:44.409,0:13:46.863
divided by two.

0:13:46.863,0:13:50.311
But we discovered it by self-exploration.

0:13:50.311,0:13:56.391
So, in addition to learning some useful geometry,

0:13:56.391,0:14:00.778
the child has been exposed to some pretty sophisticated

0:14:00.778,0:14:03.805
science strategies, like reduction,

0:14:03.805,0:14:06.719
which is the art of

0:14:06.719,0:14:10.305
transforming a complex problem into a simple one,

0:14:10.305,0:14:12.674
or generalization, which is at the heart

0:14:12.674,0:14:15.517
of any scientific discipline,

0:14:15.517,0:14:18.107
or the fact that some properties are invariant

0:14:18.107,0:14:21.131
under some transformations.

0:14:21.131,0:14:24.416
And all this is something that a very young child

0:14:24.416,0:14:28.725
can pick up using such mobile apps.

0:14:28.725,0:14:31.819
So presently, we are doing the following:

0:14:31.819,0:14:36.128
First of all, we are decomposing the K-12 math curriculum

0:14:36.128,0:14:39.019
into numerous such apps.

0:14:39.019,0:14:41.596
And because we cannot do it on our own,

0:14:41.596,0:14:44.690
we've developed a very fancy authoring tool

0:14:44.690,0:14:47.965
that any author, any parent or actually anyone

0:14:47.965,0:14:50.318
who has an interest in math education,

0:14:50.318,0:14:53.590
can use this authoring tool to develop similar apps

0:14:53.590,0:14:56.995
on tablets without programming.

0:14:56.995,0:15:00.215
And finally, we are putting together an adaptive ecosystem

0:15:00.215,0:15:03.043
that will match different learners

0:15:03.043,0:15:08.420
with different apps according to their evolving learning style.

0:15:08.420,0:15:10.941
The driving force behind this project

0:15:10.941,0:15:13.888
is my colleague Shmulik London,

0:15:13.888,0:15:16.532
and, you see, just like

0:15:16.532,0:15:20.605
Salman did about 90 years ago,

0:15:20.605,0:15:24.576
the trick is to surround yourself with brilliant people,

0:15:24.576,0:15:27.332
because at the end,

0:15:27.332,0:15:29.235
it's all about people.

0:15:29.235,0:15:32.654
And a few years ago, I was walking in Tel Aviv

0:15:32.654,0:15:35.484
and I saw this graffiti on a wall,

0:15:35.484,0:15:37.275
and I found it so compelling

0:15:37.275,0:15:39.418
that by now I preach it to my students,

0:15:39.418,0:15:41.684
and I'd like to try to preach it to you.

0:15:41.684,0:15:43.424
Now, I don't know how many people here are familiar

0:15:43.424,0:15:45.252
with the term "mensch."

0:15:45.252,0:15:47.860
It basically means to be human

0:15:47.860,0:15:49.795
and to do the right thing.

0:15:49.795,0:15:52.224
And with that, what this graffiti says is,

0:15:52.224,0:15:54.310
"High-tech schmigh-tech.

0:15:54.310,0:15:56.873
The most important thing is to be a mensch." (Laughter)

0:15:56.873,0:16:00.268
Thank you. (Applause)

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(Applause)