They deem that everything has its reason to exist only if it actually exists in this world.

他们认为万事万物只要存在于这个世间，就一定有它存在的理由。

youdao

If it actually exists it must be somewhere, and, assuming its place to be accessible to you, you can verify its factualness by direct observation. Take the case of the White House.

如果它实际存在，它必定在某处，而且，假如那个地方你很容易进去，你可以直接观察查证它的真实性。

youdao

So what actually turns out the reality is that h e 2 does exist, but it exists as the weakest chemical bond known, and it wasn't, in fact, even found to exist until 1993, so I can assure you this is not a bond that you see very often in nature, and it is a very, very weak bond.

实际上He2键是存在的，但它是目前所知的最弱的键，直到1993年它才被发现，所以我可以向你们保证在,自然界你们不可能经常看到它，它是种非常非常弱得键。

麻省理工公开课 - 化学原理课程节选

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This is a reserve in -- actually it exists in Connecticut, coincidentally enough, and it has a reserve of diesel fuel that can also be used to power generators.

WHITEHOUSE: The White House