The Holy Spirit was a testator and was numbered as a witness of Jesus:
This is he that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth. For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one. If we receive the witness of men, the witness of God is greater: for this is the witness of God which he hath testified of his Son.
The three are ONE in Christian theology, but not physically one. Jesus prayed to the Father concerning the Twelve: "...that they may be ONE, even as WE are ONE." It's a oneness of purpose. But for the Holy Spirit to be a witness and be able to testify (as, say, in a court of law), He would have to have an identity.
To say He is an "active force" -- like electricity -- and nothing more, it wouldn't make sense.