由此可知/看來/可見grammar point · tier 1 · 由此可知/看來/可見 from this one can conclude (inferential connector)
Stands on the fact just stated and draws the conclusion that follows from it: 可知 one can know, 看來 it appears, 可見 one can see — the inference grows out of the evidence on the line before.
字源 FORM what the parts do
由 marks where a thing sets out from, its source. 此 plants a foot on this spot, the fact just laid down. 可 says one may, and 知/看/見 is the knowing, looking, seeing. Together: from this point one is now able to know — the conclusion that this evidence lets you reach.
故事 STORY a scene to remember it by
A foot comes down on the ground just covered, and from that spot a shoot rises into view.
字源自撰記憶法
框 · Frame
[evidence stated]，由此可知/看來/可見，[conclusion]。
觸 · Trigger
You have laid down a fact and want to mark the conclusion you draw from it, in written or formal register.
序 · The move
1State the evidence as a full clause first.Is the conclusion something a reader infers from this, not the same fact restated?
2Set 由此可知 / 由此看來 / 由此可見 after it, fenced off by commas.Does 此 point back to the clause just written, not forward to what comes next?
3Write the conclusion the evidence supports.可知 / 可見 for what one now knows; 看來 for how it now appears.
例 · Examples
1就算再忙，他還是會去當志工serve as a volunteer，由此可知from this one can know/看來/可見，他是一個熱心warm-hearted (the conclusion)的人。
Even when he is busy, he still goes to volunteer; from this one can see he is a warm-hearted person.
Both carry 由. 由於 heads the cause and the result follows (effect drawn from cause); 由此可知 stands after the evidence and the speaker's conclusion follows (inference drawn from evidence). Direction flips: 由於 looks back to a source, 由此可知 looks forward to a judgement.
所以 links a cause to its real-world effect; 由此可知 links stated facts to what the speaker now infers about them. 所以: it rained, so I stayed home. 由此可知: he volunteers, from this we judge his character.
由此可知，他還是會去當志工。 ✗ → 他還是會去當志工，由此可知，他是熱心的人。 ✓ (the evidence comes first; 由此可知 introduces the conclusion, not the evidence)
由此可知這件事。 ✗ → 由此可知，他很熱心。 ✓ (the conclusion is a judgement the evidence supports, not a bare object)
因為他去當志工，由此可知他很熱心。 ✗ → 他去當志工，由此可知他很熱心。 ✓ (no 因為 in front; 由此 already points back to the evidence)
English 'therefore' / 'so' can mark either a real-world consequence or an inference; 由此可知 marks only the inference, and 此 must point back to evidence already on the page, so it cannot open a thought the way English 'so' can.