Ackoff's Best

Ackoff's Best, by Russell Ackoff is an excellent book by (isbn 978-0-471-31634-3). As usual I'm going to quote from a few pages:
Analysis looks into things; synthesis looks out of things … Analysis yields knowledge; synthesis yields understanding … The former enables us to describe; the latter, to explain … In analytic thinking, the thing to be explained is treated as a whole to be taken apart. In synthetic thinking the thing to be explained is treated as part of a containing whole. The former reduces the focus of the investigator; the latter expands it … Synthesis, or putting things together, is the key to systems thinking just as analysis, or taking them apart, was the key to Machine-Age thinking.
The essential properties of a system taken as a whole derive from the interactions of its parts, not their actions taken separately. Therefore, when a system is taken apart it loses its essential properties. Because of this - and this is the critical point - a system is a whole that cannot be understood by analysis.
Organisms and organisations are systems that usually have purposes of their own. However, the parts of an organism (i.e., hearts, lungs, brain) do not have purposes of their own, but the parts of an organisation do … An organisation with purposeful parts almost inevitably generates internal conflict … An organisation is a system whose major deficiencies arise from the ways its parts interact, not from their actions taken separately.
Automation is fundamentally different from mechanisation. Mechanization has to do with the replacement of muscle; automation with the replacement of mind.
The publicly owned company became a corporation (derived from "corpus", meaning "body") and the chief executive became the "head" of the firm.
Development of individuals and corporations is more a matter of learning than earning.
The most variety-decreasing type of social system is one we call a bureaucracy. A bureaucracy is an organisation whose principal objective is to keep people busy doing nothing. … The problem created by people who are busy doing nothing is that they frequently obstruct others who have real work to do. … Bureaucracies obstruct development. … Because bureaucracies tend to be inefficient and obstruct development they invite and encourage corruption.
If you're going to sin, sin against God, not the bureaucracy. God will forgive you but the bureaucracy won't. [Admiral Hyman G. Rickover]
Wisdom is the ability to see the long-run consequences of current actions, the willingness to sacrifice short-run gains for larger long-run benefits, and the ability to control what is controllable and not to fret over what is not … Even the best planning of which we are capable requires at least as much art as it does science … Planning is not an act but a process …
Today's students are over instructed in what they can better do alone: take things and concepts apart; and they are under instructed in what is very difficult to do alone: put what they have learned together into an understanding of the world and their role in it.
Effectiveness is evaluated efficiency. It is efficiency multiplied by value, efficiency for a valued outcome. Intelligence is the ability to increase efficiency; wisdom is the ability to increase effectiveness … Growth does not require an increase in value; development does.
Separation of the relevant information from the irrelevant is a critical part of problem formation … the reasons for wanting to answer a question determines what is the right answer to it.
A wrong solution to the right problem is generally better than the right solution to the wrong problem, because one usually gets feedback that enables one to correct wrong solutions, but not wrong problems. Wrong problems are perpetuated by right solutions to them.
Even those aspects of an organisation's future that are not affected by what it and others do (e.g. the weather) cannot be forecasted well for more than a short period. As in the case of the weather, however, the need to forecast it can be eliminated by bringing it under control, as we do by building structures within which work can proceed whatever the external weather may be.

stuka pilot

is an excellent book by Hans Ulrich Rudel (isbn 978-1908476876). As usual I'm going to quote from a few pages:
He tells me that a large scale offensive is in preparation in my sector... approximately three hundred tanks are to be employed in this operation... The number three hundred flabbergasts me... I reply that I find some difficulty in believing it... He says to me, half in earnest, half in jest: "If I didn't know you, for two pins I would have you put under arrest for saying such a thing. But we will soon find out." He goes to the telephone and is connected with the Chief of the General Staff. "You have just given the Fuhrer the figure of three hundred tanks for operation X." "Yes I did." "I want to know the names of the divisions concerned with their present strength in tanks. I have somebody with me who is well acquainted with the position." ... the Chief of the General Staff has the bad luck to begin with the 14th armoured division. He says it has sixty tanks. Goering can hardly contain himself. "My man reports that the 14th has one!" A lengthy silence at the other end of the line. "When did he leave the front?" "Four days ago." Again silence. Then "Forty tanks are still on their way to the front. The rest are in repair shops on the line of communications, but will certainly reach their units by zero day, so that the figures are correct." He has the same answer for the other divisions. The Reichsmarschall slams down the receiver in a rage. "That is how it is!" The Fuhrer is given a totally false picture based on incorrect data and is surprised when operations do not have the success expected... The South Eastern zone with its network of communications is being incessantly blanketed by the enemy's bomber formations. Who knows how many of those forty tanks, for example, will ever reach the front or when? Who can say if the repair shops will get their spare parts in time and if they will be able to complete their repairs within the specified time?
In ministries and departments, however, mistakes are denied on principle.
Another confirmation of the truth of our old Stuka maxim: "Nothing comes off - except what you have practised."
We have long since ceased to develop practice from theory; we do just the opposite.
The fitters have their hands full, for the aircraft have been heavily damaged by flak. The life of such an aeroplane will always be limited.
Little by little I discover all the tricks. Skill is often the result of getting hurt.
I now see that perfectly plainly. We are alone to possess this knowledge; the responsibility is ours.

the power of pairing

In a previous post I talked about an example where a pair performed better than either individually. Here's another small example that happened to me today.
My very good friend Syver was running a coding dojo in Erlang. A test for the filter exercise looked like this:
odd(Integer) when Integer rem 2 == 1 ->
    true;
odd(_) ->
    false.

filter_test() ->
    ?assertEqual([3, 1], 
      filter(fun(Elem) -> odd(Elem) end, [1, 2, 3, 4])).    
I don't know Erlang at all, so Syver helped me out with this first-cut version:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail]) ->
    filter_helper(Fun(Head), Fun, Head, Tail, []).

filter_helper(true, Fun, TrueElement, [Head|Tail], Result) ->
    filter_helper(Fun(Head), Fun, Head, Tail, [TrueElement|Result]);
filter_helper(true, _, TrueElement, [], Result) ->
    [TrueElement|Result];
filter_helper(false, Fun, _, [Head|Tail], Result) ->
    filter_helper(Fun(Head), Fun, Head, Tail, Result);
filter_helper(false, _, _, [], Result) ->
    Result
I realized Erlang is a lot like Prolog which I knew in the dim and distant past. I stared at the code and after several minutes something about it started nagging me. It was the splitting of the list into it's Head and Tail elements in both filter and filter_helper. I wondered if this duplication could be avoided by making filter_helper call back into filter. After several false attempts I came up with:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail]) ->
    filter_helper(Fun(Head), Fun, Head, Tail).

filter_helper(true, Fun, TrueElement, List) ->
    X = filter(Fun,List),
    [TrueElement|X];
filter_helper(false, Fun, _FalseElement, List) ->
    filter(Fun, List).
Then Syver showed me how the use of X could be collapsed:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail]) ->
    filter_helper(Fun(Head), Fun, Head, Tail).

filter_helper(true, Fun, TrueElement, List) ->
    [TrueElement|filter(Fun, List)];
filter_helper(false, Fun, _FalseElement, List) ->
    filter(Fun, List).
We did some argument renaming:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail]) ->
    filter_helper(Fun(Head), Fun, Head, Tail).

filter_helper(true, Fun, Head, List) ->
    [Head|filter(Fun, List)];
filter_helper(false, Fun, _, List) ->
    filter(Fun, List).
Then Syver noticed that we could pass Head,Tail as a single [Head|Tail] argument:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail]) ->
    filter_helper(Fun(Head), Fun, [Head|Tail]).

filter_helper(true, Fun, [Head|Tail]) ->
    [Head|filter(Fun, [Head|Tail])];
filter_helper(false, Fun, [_|Tail]) ->
    filter(Fun, Tail).
We agreed that filter_helper was better as filter:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail]) ->
    filter(Fun(Head), Fun, [Head|Tail]).

filter(true, Fun, [Head|Tail]) ->
    [Head|filter(Fun, [Head|Tail])];
filter(false, Fun, [_|Tail]) ->
    filter(Fun, Tail).
As a final polish Syver refactored to this:
filter(_, []) ->
    [];
filter(Fun, [Head|Tail] = List) ->
    filter(Fun(Head), Fun, List).

filter(true, Fun, [Head|Tail]) ->
    [Head|filter(Fun, [Head|Tail])];
filter(false, Fun, [_|Tail]) ->
    filter(Fun, Tail).
and then, again, after the dojo, thanks to Syver's comment below, to this:
filter(_, []) ->
    [];
filter(Fun, [Head|_] = List) ->
    filter(Fun(Head), Fun, List).

filter(true, Fun, [Head|Tail]) ->
    [Head|filter(Fun, [Head|Tail])];
filter(false, Fun, [_|Tail]) ->
    filter(Fun, Tail).
We agreed that the final version was definitely better than either of us could have come up with individually.

salmon fishing

is an excellent book by Hugh Falkus (isbn 0-85493-114-9 ). Unusually I'm going to quote from one page - the preface:
No creature on earth treats the dogmatist more sternly than Salmo salar.
Contradictory in everything he does, Salmo cannot be tied down by dogma.
In addition to providing days of rare enchantment, it taught me that much of what of what I had read about Salmo's behaviour was pretty dubious. Often, the fish I was watching seemed a different creature from the one encountered in print. And over the years it began to dawn on me that far from being fact, a lot of what I had hitherto taken for granted was indeed fallacy; that most authors had written about what they thought salmon did, not what they had seen them do.
Since then I have tested certain of their statements, some of which will be found amongst these pages: assertions by acknowledged experts and regarded as Gospel - but unsound. Most of the accepted tenets of salmon fishing started as conjecture; but gradually, parroted by writer after writer, part of this conjecture became "fact".
In salmon fishing there is no magic substitute for water-sense, skilful presentation, and persistence.
We are wise to move with the deliberation of the heron, that most stealthy of waders.
I think small hooks are preferable to big hooks - they usually get a better hold.
I remain convinced that black is the most attractive colour for a salmon fly.
I suggest that the nearest we can come to a definitive statement is to say that salmon tend to react to large flies sunk deep at temperatures below 45°, and to small flies near the surface at temperatures above 50°.