Ambivalence..

When two conflicting concepts sound equally compelling, it can mean one of the following

1. That it's a case of incomplete understanding of one or both of them
2. That the context separating them is so thin, that it tends to get overlooked
3. That the context separating them may be thick, but tends to get overlooked anyways
4. That one of them is clearly wrong! but is pedaled for some vested reason
5. That one is utopian and the other pragmatic

But I've just stumbled across a conflict that has me beat as it can't seem to be explained by any of the above.

Economists Milton Friedman and John Maynard Keynes (considered two of the greatest of the 20th century) decided that they'd polarize the world around two opposing ideologies.

Milton was an advocate of the 'free market' (no force on the markets from anyone including the government)
Keynes was the inventor of Keynesian-ism which advocates government intervention as and when appropriate

In this video - 

Milton makes a compelling case for the absolute need for no government intervention. 

• He sets the stage by asserting that - even the best of intentions of an individual (and by an entity such as a government) should not be enforced onto another individual. 
• That the integrity of the 'self' is paramount i.e - don't do good or bad for others, but just let one be!
• The reason he says is because even the best of intentions would be corrupted in the hands of authority - Absolute power corrupts absolutely! 
• He makes two profound observations in that both Sincerity and Philanthropy are overrated! 
• To substantiate the point on sincerity - he brings out the example of Hitler and Mussolini - the former more sincere in his cause and therefore more dangerous to the world as opposed to the latter who lacked absolute conviction!

Hard to refute, but why was it that this approach/philosophy actually failed during the Great Depression of the 1930's ? or even for the current Financial crisis ? On both these occasions - it was actually Keynes theory of 'government intervention' that saved the blushes for those who followed it..

Keynes essentially postulated that (severely paraphrasing and simplifying) 

• When a country is going through a bust cycle (invariably following a boom), instead of letting the markets to 'self-correct' over the long run
• It may in-fact be prudent for the government to intervene and stimulate the economy through assertive fiscal policy
• This stimulation has the net effect that aggregate demand (of goods and services) in the economy is increased and therefore leads to a subsequent increase in aggregate supply leading to economic growth which is to be continued till this growth becomes self sustainable
• Sorta like kick starting a 2 wheeler once it has slowed down, until the engine cranks up and starts running

Here's a video from Khan Academy that explains Keynesian-ism

We are living in a time where both of the above are being tried out simultaneously :

• The former policy of non interference from the government in Europe
• The latter Keynesian option in the United States

At this point, the scoreline reads Keynes - 1, Free Market - 0

But the point of my post was - 
How does one reconcile Friedman's hypothesis with it's anti-thesis from Keynes, if one agrees with the logic of respect for the 'self' and non interference from individual or entity (govt.)? 
How would Milton have defended his words in light of the Financial crisis of 2008 ?
Is there a Reason 6 that explains this discrepancy ?

In general - Is there an inherent futility in being wedded to a single concept/philosophy ?