The phrase "an external observer" is correct and usable in written English.
It can be used when referring to someone who is watching or analyzing a situation from outside, without being directly involved.
Example: "From the perspective of an external observer, the team's dynamics appeared to be quite effective."
Alternatives: "an outside observer" or "a third-party observer".
She alerted the local authority, which sent in an external observer who confirmed her fears.
To an external observer, the events of those August nights passed in the blink of an eye.
"I want visitors to feel enveloped, wrapped-up and involved in the experience, rather than adopting the position of an external observer".
"My impression — as an external observer, and that's what I am now — is that the response has been quite competent," said Dr. Julio Frenk, a former Mexican health minister who is now dean of Harvard's School of Public Health.
"It's a little bit curious for an external observer because it seems to be fast, it seems to be too much at once, but that's actually what we have promised," Mr. Kovacs said.
The result of the Nash equilibrium is not always a satisfactory outcome for an external observer (e.g., prisoner's dilemma game).
To overcome this problem in part, a blinded external observer could be used to provide objective and observational measures of functional outcomes.
To a hypothetical external observer, the initial phases of the new life of the selected individuals will appear utterly chaotic, but in due course order and regularity would emerge: "…in place of an incoherent multitude, all seemingly acting at random, we should have a social and economic organization, every member of which had his appropriate place and function" (55 56).
When professional footballers, no matter the code, speak of style, they're usually referring to something that's apparent to the external observer, a technical calling card or a way of moving on the field that's somehow idiosyncratic or unique: David Campese and his goosestep, the Sonny Bill Williams offload, Cristiano Ronaldo's motor legs and fabulously still dribbling head.
Because of the significance of these elections and the widespread belief that transgressions occurred in previous ones, there will be a large internal and external observer presence.
Unlike the quantum framework, general relativity allows no place for an outside observer or external clock, because there is no "outside".
