I am always confused about these words. for example let's consider these sentences:

  1. Doctors can now detect very small amounts of dangerous chemicals in the body.

  2. The professor asked us to identify several types of whales.

I think we used detect in the first one because it is not obvious to find dangerous chemical.

Is it all? We use detect for something not obvious otherwise we use identify?

  • What did you find when you looked up identify and detect in the dictionary, and why didn’t that help?
    – ColleenV
    Jan 13, 2021 at 16:04
  • 1
    You might detect something without knowing what it actually is. But to identify it means both detecting (being aware of) it and knowing what it is (what it's called, what it does, or whatever). Jan 13, 2021 at 17:40

1 Answer 1


You use "I have detected [some object]" when you have found an instance of that object. You already knew what a [some object] is, and you have been looking for them. And now you have seen this thing, and you recognise it as being [some object]. You have detected a [some object].

You use "I have identified [some object]" when you already know that object is there. You have studied it, and having done so you now know what [some object] actually is.

So you would normally complete the though as "I have identified the [some object] as being an instance of a [some specific type of object]."

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