# Can we use "but" to stand out only one specific agent?

I wrote this sentence:

Unfortunately, the exact velocity cannot be calculated analytically, but by making use of computers.

Can we use "but" to declare that only one specific agent can fulfill the task described in the previous passive sentence?

Analytical calculation is a type of calculations in which you solve a problem using mathematical identities and formulas. For Instance, 2x=4; x=4/2 => x=2.

• Except would have to be used instead of But, as in Unfortunately, the exact velocity cannot be calculated analytically except by making use of computers. Aug 15, 2016 at 8:18
• Yes, you can, but it would have been more common in centuries past. "You cannot obtain that permission but by formal waiver." Many readers would find it confusing today. If you do, better to leave out "making use of".
– TimR
Aug 15, 2016 at 10:07
• Leaving out "making use of" because that is what by already means in this construction.
– TimR
Aug 15, 2016 at 10:26
• The challenge to be overcome is the opposition of manner (calculated analytically) to thing (computers). It is a little jarring. Compare: "Unfortunately, the notes of the minimalist techno composition are so rapid that it cannot be played with human hands but by synthesizer."
– TimR
Aug 15, 2016 at 10:36
• @TRomano great; consider this: "Unfortunately, the exact velocity cannot be calculated analytically, but by making use of numerical methods"; "numerical methods" is the opposite of "analytical calculations" Aug 15, 2016 at 10:39

As I understand it, you want a sentence that has this meaning:

Unfortunately, the exact velocity cannot be calculated analytically without the use of computers

Although but can mean except, the but by collocation gives a strong suggestion that the following clause is a complete alternative to the previous clause, so your sentence is most likely to be interpreted as follows:

You cannot calculate the velocity analytically, but you can calculate it using computers.

Here are a couple of examples that shows but by used in this way:

Most sword fights are not won by such skill, but by brute strength - Excalibur: a novel. Bernard Cornwell, 1999

The mayor is chosen annually, not by the citizens as in other corporations, but by the majority of the other members of this court the Eighteenth century constitution

I therefore suggest that you use a sentence like the one at the start of this answer, or alternatively use one like this:

Unfortunately, the exact velocity cannot be calculated analytically except by computer.

• (+1) Thanks for the answer. My intention is exactly as what you mentioned: "You cannot calculate the velocity analytically, but you can calculate it using computers." Aug 15, 2016 at 10:26