[lumberjack]

The problem with smart contracts is that they are only 100% trustless as long as all the input data is already present on the blockchain.

Even something banally simple as "if such and such win the world cup deposit earnings there" cannot be 100% trustless. How does one overcome this problem?

I don't think smart contracts can overcome this problem while remaining 100% trustless.

[7373737373]

"Trustless" is a terrible meme, as the term is misleading and the implementation of the concept is impossible. The truth is:

There is no cloud, just other people's computers.

Smart contracts can make trust relationships explicit.

By using a blockchain system, you entrust a network - which you may have no control over - with application state. If you rely on such a network, you indirectly also rely on the network infrastructure and operators' social and economic incentives.

[leashless]

I agree that our terminology is often terrible. "Smart contract" could well have been "conditional payment" which for most purposes is clearer.

Do you know about http://erights.org ? They are good - great - on terminology.

[nicksdjohnson]

I agree "smart contract" is a poor term, but they're way more than "conditional payment" - you can do a lot of things with them that have nothing to do with paying money.

[7373737373]

Yes, in fact this is one of the most interesting websites for me now, especially when looking at general purpose distributed computing beyond blockchains. See here for a few notes of mine: https://github.com/void4/notes/issues/5

[rabbyte]

if we're going to simplify language then call it what it is: a program. the only reason they're called contracts is because they were theorized within the context of future financial instruments, smart contract is a historical artifact for a kind of automated thing that might have one day appeared in many forms, but now we know. calling them programs would have been more immediately accessible to programmers which is clearly where the weight is shifting, contract should have been reserved for the DSL lawyers use to write programs. ¯\_(ツ)_/¯

[cslarson]

Yes I think this is right and we lose something when we limit to finance or legal terminology.

[mwnivek]

This may not fully address your questions, but oracles input external data into smart contracts:

https://docs.oraclize.it/

[kolinko]

Trustlessness is not a requirement for having a robust system.