You can't have it both ways

My cousin (and president of Birmingham Uni's Atheist society) Benjamin reposted a YouTube video which argues that Christians don't have the objective morality they can often claim to have, they have a subjective morality like everyone else.

OK, so here's a bit of a response, as per these debates I'd be very surprised if it got anywhere, but here goes!

The real problem with the argument is that it fails to distinguish between a command and a moral principle, so for example when the antagonist says: "Today's the sabbath, they're supposed to be put to death if they worked (Exodus 31:15)" the Bible verse is talking about a command, not a moral principle.

The underlying command: that of having a day of rest is still valid (Ex 20:10). Similarly, Lev 20:10 the underlying principle of not committing adultery is still valid. Similarly, Deut 21:18-21 and Prov 20:20, honouring your parents is still a moral principle. So it turns out that all the moral points the verses refer to are still valid, and so the argument here against objective morality doesn't stand.

In which case the Christian's argument is valid insofar that the New Testament maintains that the O.T morality is correct, though the way our failure to maintain it isn't: that's what the New Covenant in Jesus is about.

What's not quite right is the Christian's statement: "The old laws were made in the context of a very different culture and time period." What's happening here is that DarkMatter2525 is injecting the antagonist's definition of subjective morality here as an explanation for the difference between the Old and New Covenant.

In reality, the difference with the New Covenant has nothing to do with a change in the culture and time period. It's to do with the fact that (a) the Old Testament demonstrates that Israel couldn't keep the morality embodied by the law by their own efforts (and neither can we), Rom 3:2-21 (b) Jesus did keep it and because we can be 'in him', God's agreement with Israel is shared with us: Rom 8:3-4.

The key thing here in Rom 8, goes to the heart of what morality is about, since the natural question to ask is why the command in Ex 31:15 is not the same as the principle in Ex 20:10 when both appear as commands. That I'll leave for another time.

-cheers from julz

For reference, here's the transcript:

(Calm expression) "Morality is subjective, the perception of Morality depends greatly on the on context of the culture and the time period. As such it can be uniquely defined and subject to change."

(Angry) "NO, morality is objective, morality comes from God and God doesn't change. A sin is a sin no matter when or where. What's wrong today was wrong yesterday and what's wrong here is wrong everywhere."

(Calm)"Did any of your friends or family do any work today?"

"Yeah."

"Today's the sabbath, they're supposed to be put to death if they worked (Exodus 31:15). And according to the Bible you should condone the killing of adulterers and witches, disobedient children.. (more Bible verses: Lev 20:10, Deut 21:18-21, Prov 20:20, Lev 20:9, Ex 21:15)"

(Shock)"Oh my God! What's That?" (points right, antagonist follows)

"What - What?" ( Christian steals the "Subjective" heading from his antagonist and replaces his old "Objective" heading with it)

"Uh, I guess it was nothing. Anyway, that was the Old Testament, there's a new covenant with Jesus Christ. The old laws were made in the context of a very different culture and time period."

"Hey, you just stole my word."

"I don't appreciate these accusations, why the Hell would I..."

"Hey, Look out!"

"Yeah, right, like I'm gonna faaeeuugghh." (gets eaten by Alien).

FIGnition oxo game! (noughts and crosses/ tic-tac-toe)

After my doom and gloom blog about the arctic, I thought I'd write a bit of a journal on how to write a simple noughts and crosses game. So, this'll be technical, and fairly involved as it'll include code, but at the same time will give a bit of insight into FIGnition, Forth and simple strategy games.

FIGnition is a real 80s-style computer. It's got enough memory (8Kb) to write simple programs and enough built-in storage to develop them in. The keyboard's somewhat awkward, but I'm getting used to it (I designed it).

The Computer History Museum is running an event called Hacker's delight, and as I'm exhibiting, they've asked me to produce a version of noughts and crosses to be demoed there. Demoing the development is as important as playing the game.

I started by looking at a few versions of tic-tac-toe. It's possible to write a recursive min-max algorithm, but I took my original cue from an online version of Not Only 30 Programs for the Sinclair ZX81. There are some insights into playing the game here.

Firstly, how to number the board. The board is numbered not in the order:

1|2|3
-+-+-
4|5|6
-+-+-
7|8|9

But

1|2|3
-+-+-
8|0|4
-+-+-
7|6|5

And it's done this way to make it easier to analyse the board. Opposite corners have a difference of 4 and subsequent diagonals have a difference of 2. In fact it's best to represent the board like this, because it reflects the real structure of a oxo board: if you rotate it by 90º it's still the same.

So let's first convert the ZX81 game. The ZX81 version simplifies the game by making the computer go first, by placing an 'X' in the centre. It then follows the following strategy:

• In the first move (A=1), the computer plays the opponents move+1 (so, if the user played to middle, the computer plays to the next corner and if the user plays to the corner, the computer plays to the next middle).
• In all other moves, if the user fails to block, then the computer plays opposite of the previous move and wins (i.e. because the user failed to block).
  
• Otherwise, for the computer's third move if the user had played to the middle of a row in its first move then we step 1 back from our previous move and win. (That's our other winning case). That's because the computer's second move always creates a dual two-in-a-row where the previous location is its other winning choice.
  
• Otherwise for the fourth move then we backwards by 2 and it's a draw.

It's a really simple strategy, which if you note, doesn't involve responding directly to the user's moves, except to record whether they first played on an odd or even square or whether they last blocked the computer's move.

In Forth we can simplify it by representing the moves as a table, one set for when the person played to an even-numbered square and the other set for when the person played to an odd-numbered square:


cdata compMoves 1 c, 2 c, 7 c, 0 c, 1 c, 2 c, 3 c, 6 c,

And then the algorithm simplifies to:

• If the user didn't block or we haven't played yet, then pick the next move from the table adding it to our current position and if the move was '7' we win, else if it was a '6' we draw.
  
• Otherwise we move to the opposite side of the board to our last move and win.

In Forth this is:


: compPlay ( movnum comp h -- m c f )
dup opp + brdRange = ( m c h h+4=c )
>r over = r> or if
over compMoves + c@ dup >r + r>;
7 =
else
opp + 1
then
;

An entire oxo game in approximately 9 lines of code! The entire game is listed on the FIGnition website and also here. It takes up approximately 5 screens and 554 bytes.

( Simple oxo )
: 2drop drop drop ;

: .brdLine
cr ." -+-+-" cr ;

: . Board
." 1|2|3" .brdLine
." 8|X|4" .brdLine
." 7|6|5" ;

4 const opp
64 15 + const (o)
64 24 + const (x)

: cdata <build does> ;

0 var board

cdata posConv
0 c, 0 c, 1 c, 2 c,
5 c, 8 c, 7 c, 6 c,
3 c,

: pos2xy posConv + c@
3 /mod 1 << swap 1 << swap ;

: place ( pos ch -- f )
over 1 swap << board @ swap over or 2dup =
if ( pc old nu )
2drop 2drop 0
else
swap drop board !
swap pos2xy at emit 1
then ;

: range? (val lo hi -- val | 0 )
rot swap over <
>r swap over > r>
or if drop 0 then ;

: humPlay
0 begin drop
begin
key 49 57 range?
dup until
48 - dup (o) place
until
;

: brdRange 1 - 7 and 1+ ;

cdata compMoves
1 c, 2 c, 7 c, 0 c,
1 c, 2 c, 3 c, 6 c,

: compPlay ( mv c h ..)
2dup opp + brdRange =
>r over = r> or if
over compMoves +
c@ dup >r + brdRange
r> 7 =
else
opp + 1
then
over (x) place drop
; ( .. -- mv c f )

: init 0 board ! cls .brd
;

: win? 5 0 at
?dup if
." I WIN!" key drop 1
else
over compMoves + c@ 6 =
?dup if
." DRAW!" key drop 1
else 0 then then ;

: oxo
init humPlay dup 1 and
4 * swap dup
begin
compPlay win?
0= while
swap 1+ swap humPlay
repeat
2drop ;

In a future post I'll look into a more sophisticated (2Kb!) version of noughts and crosses: where the person can start first, where I use real UDGs for a full-screen display and where the computer can LOSE ;-) !

Arctic Smashed

I've been doing some simple analysis of the arctic sea ice extent data in order to generate my own prediction of the summer low. I'm now almost entirely convinced that the 2011 record will be smashed in 2011.

I've based it on the Jaxa arctic data from 2002 to 2011, which I imported into a gnumeric spreadsheet. You can see from the initial image that the SIE for 2011 is below the record-breaking year 2007 and has been every day since mid-May. In itself, this should be cause for alarm, but let's go back to 2007 to see why it's even worse than you might think.

2007 was a record-breaking year, but it didn't look that way until it lurched into free-fall in the last 10 days of June, due to a 'perfect-storm' of (AGW-induced) weather conditions, which set the scene for a record loss in late September. So the fact that 2011 has been lower since May isn't conclusive.

So, what I did was take the Jaxa data an import it into a spreadsheet. My first estimates were based simply on the ice loss from previous years after July 16 bolted on to July 16, 2011. There I discovered that the SIE minimum for this year would be about 4.16million KM2 - a new record, but not by much, a mere 80,000Km2. What's scary though is that simply bolting on the curves means that we'd get a record for 7/9 of the previous 9 years.

July 16: 2011	7347656
Year:	2010	2009	2008	2007	2006	2005	2004	2003	2002
Minimum:	4813594	5249844	4707813	4254531	5781719	5315156	5784688	6032031	5646875
July 16	8025000	8342969	8423438	7592500	8079844	8401094	9029375	8858281	8832969
Simple Prediction:	4093125	4199219	3549219	3911874	5024844	4174218	4058906	4426406	4077187
Average:	4168333

But it's not a realistic estimate - it's likely to be an underestimation. That's because SIE curves tend to have some continuity between the current state (and conditions) and the future state. So I constructed a slightly better estimation. In this one, I calculated the slope of the ice loss from July 1 to July 16 and compared the ratio with the eventual ice-loss at the minimum SIE for every year.

July 1 to July 16:	1715157
Year:	2010	2009	2008	2007	2006	2005	2004	2003	2002
July 1-July 16:	781563	1379844	1221562	1696406	1158750	1214375	1031250	1108750	1210937
Ratio to min SIE	5.11	3.24	4.04	2.97	2.98	3.54	4.15	3.55	3.63
July 1-16 Extrapolated:	3.002E+05	3.503E+06	2.131E+06	3.973E+06	3.946E+06	2.989E+06	1.951E+06	2.976E+06	2.835E+06
Average:	2.734E+06

With this, the best-case projection (i.e. maximum minimum SIE) will be 3.95million Km2 and the worst case will be 300,000Km2 (average 2.7million Km2). That's - stunning, and stunning doesn't even cover it: a 50% ice loss from 2007 in the best case, a 93% ice loss in the worst case, 33% ice loss in the average case.

The question is then how reliable these estimates are. Well, I'd be the first to say, "not very". My projections can be skewed easily by a steep anomaly in early July 2011 which would project a much lower summer minimum than would be likely.

The irony is that 2011 has had a smoothly falling curve between May and mid-July and it was 2007 which had the sudden acceleration over July. So 2007 makes my 2011 estimate look higher than it's likely to be. So, I'll stick my neck out at this point and say I figure the arctic record will be smashed this year, it's likely to be around 20% lower than 2007, probably in the range of 3.5million Km2, almost certainly lower than 4.0million Km2 and perhaps even as low as 3.0million Km2.

Flashy FIGnition!

I'm the designer and developer of the FIGnition DIY 8-bit computer from nichemachines and I'd like to share a major milestone in its development with you.

FIGnition contains 512KB or 1Mb of raw Amic Flash storage. I've been working for quite a while on making the chips work like a proper disk, like USB memory sticks do and at last it appears to work and this is a momentous achievement!

Making Flash work like a proper disk is hard, because Flash memory is a development of an old technology called EPROM, which could only be written once and then required sitting under a UV light for 20 minutes to re-initialise it all (losing all the previous data). The only difference with Flash is that you can erase it electronically. Using Flash memory is like trying to write a book with an old mechanical typewriter and without tippex, but with a portable recycling unit. Every time you make a mistake on a page or need to change it you need to pick up a new clean page. Moreover, you're not allowed to change the orders of pages so you'd end up with all the page numbers in the wrong order. It's one redeeming feature is that you can take 16 or 32 consecutively edited pages and stick them through the recycling unit to give you new clean pages.

If everyone had to type like that I figure no-one would have ever bothered.

But that's how Flash is. On the (easier-to-use) Amic chips you can write a block of up to 256b at a time ( a page ), but you can't rewrite it; and you can recycle 16 pages at a time.

This FIGnition firmware is therefore so amazing it needs a blog of its own. As far as I know it's the smallest virtual flash disk software around at only 1.5Kb of compiled 'C' code (on an AVR Microcontroller). The firmware abstracts the Flash memory so that you can read and write 512b blocks to your hearts content; it remaps them to physical flash pages on the fly and recycles all the modified pages. The algorithm is so short you could port it to the internal Flash memory of a Microcontroller and use it as a proper disk and could be converted to work with as little as 4 original 28F010 devices (128Kb drive) (or 1 AMD 29F010 device (80Kb drive)).

To give you an idea of how good this is, it's worth comparing with existing uses of Flash chips. Most standard introductions to the embedded use of Flash memory tell you to create the memory image on the host and simply write it to the target. AmForth, for example uses internal Flash memory to store programs, but if you make a mistake you have to erase the lot again: you can't Forget definitions. Butterfly basic (for the MSP430) is similar, you can write and edit over individual lines of code, but once the Flash is all used up (even if there are reclaimable areas of flash) you have to erase the lot. UCLinux (a fairly complex embedded OS) can either use the rather large MTD flash driver or be restricted to the write-once blkmem driver. The original Psion SSDs on both the Organiser II and Psion 3 systems (both far more complex than FIGnition) used sequential, variable-length records and you had to copy the entire SSD to another one when it ran out.

VDsk FIGnition's VDsk flash system is also a bit of a 19 year personal dream. In the early 1990s I was working at a embedded company called Micro control systems where we developed solid-state storage systems using the then brand-new Intel 28F010 Flash memory chips and a bit later, the early PCMCIA flash cards. They were MS-DOS based systems and you could prepare MS-DOS formatted disks in a sort of write-once procedure. I spent quite a bit of time working on a truly general purpose flash disk system, which could have appeared at the same time as the first San-Disk Flash disks. But it was never in the company's commercial interest, so it could never be justified.

Later still, I worked at Teleca.com where we base-ported Symbian OS (Nokia and SonyErricon's Smartphone platform in the early 00's) to new phone hardware. The Flash drivers were good, but formidably complex! Inbetween I toyed with variants of simple Flash filing, either targetted at an old Apple IIc or ficticious embedded systems.

But now it's done - a simple, purging, embedded Flash Disk system which supports wear-levelling and is reasonably robust in the face of sudden power failures. It's been tested for over 60,000 block re-writes (30K on 2 different device types) with no errors. Enjoy.

It's Good To Ask Questions

On facebook my cousin Benjamin shared a reference to an article in an Irish newspaper about her deconversion to Atheism and asked "I'd like to see a theist's take on this article."

So, I thought I'd take him up on it. Hope the response isn't too dry! First it'd be a good idea if you read her article - it's well written and gets to the point.

“Atheism Is the True Embrace of Reality”

Paula's article consists of two major points.

Firstly: she explores the variety of Christian beliefs and finds them completely inconsistent. Therefore you can't know anything about the truth of the existence of the Christian God.

Secondly: Atheism isn't a belief, but a rejection of beliefs not based on evidence.

The first point is essentially an argument from subjectivity. I.e. a subjective experience can't tell us anything about the existence of God. And that's kind of correct, a subjective experience isn't a basis for even determining God's existence, never mind his/her/its properties or character. And that's primarily because from an external viewpoint (which is what the observer has), the subject is simply another item within the reality we live in: a heap of well-organised DNA, generating sound waves.

The problem therefore with the argument is that it's the wrong way round. God, if he/she/it existed determines us and our reality, in a roughly analogous way to the way mathematical axioms determine valid mathematical theorems, or (going another step back) a mathematician determines the set of axioms, which then determine mathematical theorems. It's not possible to determine God's existence from subjectivity in the same way it's not possible to determine the historical existence of Euclid from the existence of parallel lines, not even if the parallel lines could say "I wouldn't be where I was today without Euclid!" ;-)

So, the problem remains, if subjectivity isn't a valid basis for believing in God's existence then what would the basis be?

So, onto the second point: "Atheism isn't a belief, but a rejection of beliefs not based on evidence". So, the questions I would raise are firstly: What is precisely meant by 'evidence' here? Secondly: Is evidence a sufficient basis for beliefs?

I suspect that what she means is scientifically attested evidence supported by a consistent rationale (although she doesn't really mention anything at all about the need for reason in connection with evidence in her article). What she doesn't mean is subjective evidence, i.e. "I went on a milkshake diet last week and lost 2Kg", even if the person could prove that they did go on a milkshake diet last week and lose 2Kg.

The issue in her part of the argument is that all her qualifying terms, such as: 'valid' (as in "a deity for which no valid evidence…") or "reality" (as in "one you have faced up to the reality that there is no evidence") end up being circular. What is 'valid' means (I presume): "scientifically attested" (i.e. attested, because repeated experiments have provided consistent evidence). What "reality" means is: the reality one can infer from valid evidence and reason, etc.

With her second point the problem again is that "evidence" can't be a sufficient basis for beliefs. Let's consider one of her statements: "there is no evidence to suggest there is another life after this one, it becomes all the more important to live this finite life to the full, learning and growing, and caring for others, because this is their only life, too.."

But this doesn't follow. If there's no life following this one, then why not just stomp on everyone else to get your own way? We're both going to die after all. Or putting it slightly differently: there's no life after this one, so why not just try and make as much money as possible? There's no life after this one so why not just party? There's no life after this one so why bother getting up in the morning? All these things, I think, follow just as well don't they?

Conversely, what if the evidence proves unpalatable ideas - should we change our beliefs? What if objective evidence in the end justifies genocide - that is that unless we bump off the weaker members of our society (e.g. religious people) then humanity is doomed. What comes first in that case?

So, as I see it, the nub of the problem is the question of what counts as a sufficient basis for anyone's beliefs on any kind. Subjective claims aren't a sufficient basis for knowing truth, but 'evidence' is a badly defined term and a complete minefield as a basis for constructing beliefs about how to live.

But it's good to ask questions isn't it?

Carjacked Honeymoon

I guess most of you already know what happened to us in brief. I thought it would be a good opportunity to write down the current situation as it's too long for a facebook status.

Anyway, this is what happened. We arrived in Naples on April 18 in the evening, about 20:35. We picked up the hire car, a basic Fiat Panda without SatNav. It took us 90minutes and I had to get an overdraft extension just to be able to pay for the excess which hadn't been specified on the form. And then we started to try and navigate our way out of Naples in dark.

Except it just wasn't easy at all - the main highway to the A3 which would take us to Sorento was blocked so we ended up going round half of Naples and in and out of the airport for thirty minutes before we found a street which sign posted a turning for the autostrada.

While we were trying to figure out whether the turning would take us in the right direction a motorbike pulled up on our left; the back passenger got off and came up to the car. I can't remember too clearly what happened next as it was a bit of a blur. The guy was gesticulating and shouting and when I expressed my confusion I saw he had pulled out a pistol and cocked it into position (by pulling the top section back, it was an automatic).

I got out of the car and wandered over to the other side of the motorbike; I saw the other guy get in as Helen got out and the first guy started pointing at my wedding ring (a fairtrade gold ring, one of the first that could be bought that way) and when I refused put his hand in his pocket to pull out a gun...

but before he could do anything a car appeared round the corner and they both sped off, leaving us without our car, clothes, money, cards, Kindle, passports etc. They took everything except the clothes we were standing in; our rings and mobile phones, only one of which had any power.

So then we spent the rest of the night stuck with the police. The incident took place just outside a house, and the occupants let us in after they saw Helen calling for help. With the help of Yahoo Babelfish we were able to explain something of what happened; they called the police (5 officers arrived); and after 90minutes where precious few details were taken we went to the main police station to take down a statement, but just ended up waiting so long we were then escorted to a hotel for the night (pre-paid for by Helen's friend Mary), where eventually the hotel managers let us in (they wanted to see our documents... which of course we didn't have).

Mostly we've been spending the rest of the honeymoon trying to get enough things into place, but it's all so terribly involved. It took a whole morning to get a fairly simple statement down. We now have some changes of clothes, a temporary passport and a little money and we've spent 2 nights in our hotel. We have yet to sort out what happened to the car and other things it's probably not best to go into details with on this blog.

However, we are completely unhurt, we must emphasize that. Many people have been very helpful, we'd like to thank the British Consulate in Naples for their extended help along with the kind support of the staff at our hotel as well as other sympathetic individuals. Thanks for all the support from all our friends, I hope this blog helps you know where we're up to.

Much love from julz and Helen

Televisors!

This is just a short - scruffy post about Televisors. A friend of mine pointed me to the MUTR website which is selling minature Televisors and it set me thinking about variations on the theme. But first some information on the Televisor frame format.

Frame Format

There are variations on the Televisor format, but here's a summary of the MUTR one.

Frame rate is 12.5Hz.
There's 32 vertical scans so each scan is 400Hz.
The original doc specifying the minature Televisor specc'd the pixels frequency at 80 pixels per scan, so each pixel is at 25.6KHz.
Voltages are similar to composite TV: 1V peak-to-peak is normal. Sync is at 0V, black is at 0.3V, white is at 1.0V.
Frame sync is the entire 32nd scan - so the 32nd hole on the disc is used to check frame sync.
Line sync (here vertical sync) uses the bottom 7.5% of each scan, the bottom 6 pixels. So, there are 74 video pixels available.

That about sums it up, now for the ideas:

Visorpong

It should be possible, just using nearly the lowest MCU available ( e.g a PIC 12F509) running at 4MHz to implement pong, producing televisor video output. Here the PIC generates up to 78 pixels per scan; that's 32 clocks/pixel with 5.8 sync pixels. I worked out a basic output routine:

btfcc TMR0,0 ;(btfcs for odd pixels).

goto .-1

movf gGpio,w

btfsc 0x10+(pix/8),7-(pix&7)

addlw 1 ;bit 0=video signal.

movwf GPIO

Which takes 6+3n where n is the number of wait loops, so we have up to 26 c for computation; about 1872 overall. There's up to 10% jitter on pixel output. There's also 196 cycles available during sync.

Digital Televisor

Similarly a more highly-specced MCU, e.g. an AtTiny25 should be able to sample incoming Televisor video and control a real Televisor disc and output video onto it. This would greatly reduce the part count and the MCU would also be able to do automatic line and frame sync.

Televisor Simulation

You don't need a 75MHz Pentium to simulate a Televisor - a ZX Spectrum with an analog in would (just) be able to keep up with converting Televisor input onto its screen, my draft routine uses 75% of CPU converting samples into dithered bitmaps, here's the core of it:

in a,(sampler) ;10c?

out (sampleTrig),a ;start next sample (data is irrelevant). 21

add a

ld e,a

ld a,(de) ;first conversion sample.

inc e

ld (hl),a

inc h

ld a,(de) ;second conv sample.

ld (hl),a

inc h

I've been trying to think about how a VIC-20 could keep pace; running it in 16 chars x 20 lines with 4x2 VIC-20 pixels per real pixel, but my best basic routine so far would take 38cycles, about 20% too slow.