Thus Spoke Zarathustra (Therefore I Listened)

Be Word Wise

Should you write 'thus' or 'therefore'?

There is endless confusion about these two words.

Warning: the confusion is made worse by faulty (read, 'plain wrong') advice offered on several so-called 'language learning' sites.

The difference between the two words is really quite straightforward.

‘Thus’ means ‘in this way’ (it’s the 'how')

If you want to say ‘in this way’, then use 'thus'.

Chances are you won’t need to use it often. It can sound a little stilted.

If it’s used properly, it can be replaced with ‘that’s how’. (So why not say ‘that’s how’?)

Example:
I found the combination, manipulated the dial and pulled open the heavy door of the safe; thus (that’s how) I retrieved my treasures.

Note that 'thus' usually starts a new clause, and is preceded by a semi-colon, not a comma.

The main problem is that people often write ‘thus’ when they should write ‘therefore’.

‘Therefore’ means ‘for this reason' (it’s the 'why')

‘Therefore’ is often about cause and effect and, in informal language, it can sometimes be replaced by 'so'.

Example:
It was raining; therefore (for this reason / that’s why / so) I took my umbrella.

Note that 'therefore' also starts a new clause, and is preceded by a semi-colon, not a comma.

In the example, above, ‘thus’ would be totally wrong. It’s not about ‘how’ I took my umbrella, but ‘why’.

Look again at the title:

Thus Spoke Zarathustra (Therefore I Listened).

It’s saying: ‘This is how Zarathustra spoke (and that’s why I listened)’.

As you would!

When they seem to be the same…

The two words are not interchangeable but sometimes they appear to be.

I’ll explain.

Look at these two sentences:

I saw he had a runny nose, a cough and a high fever; thus (that’s how) I decided he had flu.
I saw he had a runny nose, a cough and a high fever; therefore (for this reason), I decided he had flu.

They give you a good example of how ‘thus’ and ‘therefore’ seem to be the same.

In fact, the words have exactly the function I explained earlier. The sentences show firstly how and secondly why you came to your decision.

They don’t mean exactly the same thing, but it matters less because the meaning, or outcome, of the sentence remains the same.

The simplest advice:

• Ask yourself whether you are saying ‘how’ or ‘why’

• As always, be absolutely sure that the message your readers receive is precisely the one you meant to send.