(From Clarke’s answer is recorded in the the fourth edition of Samuel Clarke’s Scripture Doctrine of the Trinity and Related Writings.)
OBJ. “Three Divine Beings – must needs be conceived as Three Gods, notwithstanding any Subordination of the Second and Third Being to the First; or else we must free the Pagan World from the Absurdity of Polytheism, and the Guilt of Idolatry; these being generally, if not always, founded upon a Subordination of many Deities to the One Supreme.”
ANSW. The Difference between Christianity and Paganism, is This. The Pagans acknowledged many FALSE (fictitious) Gods, and many FALSE (fictitious) Lords: On the contrary, Christians acknowledge only One True God, and only One TRUE Lord or Mediator. There are (saith St. Paul) that are called, (that is, that were feigned1 by the Heathens,) Gods many, and Lords many; But to US [Christians,] there is but One God,[viz.] the Father, Of whom are all things; and One Lord, [viz.] Jesus Christ, By whom are all things. Now to say, that besides the One True God, there cannot be also One True Lord or Mediator; is an Argument, not against myScheme in particular; but ’tis the Argument which Deists use, (with what Reason, I have elsewhere shewn,) against Christianity in general. Or to say, that there is also indeed One True Lord or Mediator, but that That One True Lord is the same Individual with the One True God; What is This, but to affirm in other Words, that the One Lord Jesus Christ, BY whom are all things, is the One God, the Father, OF whom are all things? Which is overturning the Apostles whole Argument, and introducing an absolute Confusion of Persons. Our One God, says the Apostle, is the Father: If then the One Lord, Jesus Christ, be That One God, whom the Apostle defines to be the Father, of whom are all Things; is not this expressly affirming that the Son is the Father? Than which, nothing can be more hard to understand, or to reconcile with the whole Doctrine of Scripture.
But why must Three Divine Beings, of Necessity be conceived as Three Gods? One God, the Almighty Father; and One Lord, the Only-begotten Son of That Almighty Father; and One Holy Spirit of God, the Spirit of That Almighty Father; are in our Creed represented to us as Three distinct Agents: And yet they are no more Three Gods, than they are Three Almighty Fathers, which is (according to the Creed) the Definition of God. One God, to whom Mediation is made; and One Mediator, making Intercession for us to That One God, (which is St. Paul’s manner of speaking;) are no more Two Gods; than an Advocate with the Father, and the Father with whom that Advocate is, (which is St. John’s manner of expressing the same thing,) are Two Fathers. One Spirit, One Lord, One God and Father of all, who is above all; are by the Apostle represented to us, as Three distinct Agents: And yet they can no more truly be said to be Three Gods, than Each of them singly, (or than All of them together,) can be truly said to be The God and Father of All, who is Above All; Which is the Apostles Definition of the One Supreme God. Three perfectly co-ordinate, and equally Supreme Persons or Agents, (whatever Distinctness, or whatever Unity of Nature be supposed between them,) must of Necessity be conceived to be Three Gods, that is, Three Supreme Independent Governors of the Universe; because the proper notion of God in Scripture, and in natural Reason also, as to all moral and religious Regards, is his being absolutely ὁ παντοκράτωρ, Supreme Ruler over All, and ὁ πατὴρ πάντων, (Eph. 4:6) the Father or Author of all things: But, This Character being preserved entire, no other Power whatsoever ascribed or communicated to other Agents or Persons, can justly cause us to conceive more Gods than One. How and in what Sense the Son, though he be not That One God and Father of All, who is above All, may yet truly and properly be stiled God; has been largely explained the the foregoing Papers.2
But now on the other side, if the Father, the Son, and the Holy Spirit, be conceived to be All but One Individual Being; it follows of Necessity, that the Son and Holy Spirit have no Being at all; Which is an insuperableDifficulty in This learned Author’s Scheme. For if each of these Characters belong to One and the same Individual Being; and the Father Alone be (as is acknowledged) that Whole Being; it follows evidently that the Son and Holy Spirit, either are Themselves The Father, (which he is not willing to allow;) or else have no real Being, no Existence at all, but can only be Modes, Powers, Characters or different Denominations of That One Supreme, that One Simple and Uncompounded Being, which is the Father of All. The plain Consequence of which is, that our Mediator and Redeemer is only a Mere Man, in whom God the Father manifested himself after an extraordinary manner; and that the Holy Spirit is nothing but a mere Virtue or Operationof the Father. Which Notion, how much soever it may be defended, as an Hypothesis, by bare Reason, (as may be seen in the Socinian Writers;) yet I can by no means see how it is to be reconciled with what is taught in Scripture. Besides: Since this Learned Writer always supposes his own Scheme, to be the same with That which from the Time of the Fourth Century has been stiled Orthodox; it deserves to be remarked on the contrary, that by his plainly making the Son to be, homoousios, but tautousious with the Father, that is, One and the same Individual Being; his Assertion in reality appears to be the same with that, which from before the Days of Photinus to the Times of the Schoolmen, has by the Council of Nice, and all following Councils been condemned as Heterodox.
Special thanks to Alexander Ascuitto for transcribing this. See his site here.