What does the idiom "looking through a prism" mean?

Question

Just a few hours ago, I came across the idiom "through the prism of sth/sb" and looked up said phrase on the internet. I only managed to find one entry entitled "Through The Prism of The Prism?"on englishforums.com.

User "Blue Jay" responded to the OP's question with this:

• If you look at something through a prism, it will change how you see it. Here it is used figuratively, to indicate that her view or opinion of the past was affected by the circumstances, ideas, opinions etc. of the present. She viewed the past from the point of view of someone in the present.

Before I continue on, I should provide the original poster's sentence:

• "Could you please explain the meaning of the phrase in bold? [original sentence] She looked back at the past through the prism of the present. Thank you"

I still fail to understand this idiom's meaning. Would someone please elaborate on this idiomatic phrase?

Additionally, would someone explain what contexts it would be appropriate to use this phrase and which contexts is it not appropriate to use this phrase?

Answer 1

In the phrase "Looking through a prism", the word prism here is being used differently from the prism we use normally (being used metaphorically). Here the prism is being referred to the idea of distortion and different perspectives (as a light would do as it hits a prism), so the idiom is talking about looking at something in a completely different perspective.

This can also mean that someone has been affected by some other influence and by that the person looks at something differently from before. This idiom can also be rephrased as "seen through a prism", "looked through a prism"... etc.

An example:

"Issues are seen through the prism of religion and region."

However, we won't use this idiom when we are referring to something that wasn't changed by perspective- after all, the "looking" part can be changed by tense and the meaning is still the same, however make sure that the idiom comes after the main thing that we are talking about and precedes before what we see through.

Issues are seen through the prism of religion and region.

Answer 2

According to Collins Dictionary:

If you see something through a prism of something such as time or memory, your idea of it is affected by that thing.

Through the smoky prism of time, I could just barely make out my father as a young man.

And this example from Longman Dictionary:

He is a decent, intelligent human being who happens to see the world through a very narrow prism.

And this from Cambridge Dictionary:

Seen under this prism, the terrain vague can be thought of as an alternative public space.

Answer 3

Historically, a prism was used to break light up into a spectrum to perform spectral analysis. By breaking up the light emitted or reflected from an object into a spectrum, you can see precisely what the object is made from.

This is a spectrum of the light from our sun. The black lines are called absorption lines. These are wavelengths that are absorbed by the elements in the sun's atmosphere. Since these wavelengths can be precisely mapped to specific elements, you can use a spectral analysis to determine what elements are present in the light.

These days we use machines called spectrometers to measure spectra more precisely, and there is no need for a human to look directly through a prism; nonetheless, the idiom remains.

A prism is a tool used to break down a problem and look at it in detail. Idiomatically, a prism is a particular piece of information or perspective that one uses to understand something larger.