A quick
survey of the web reveals that the idea of our hearts being "[perpetual?] idol factories" has been extensively attributed to John Calvin. I just cannot find it anywhere in Calvin specifically. What follows are some (I think) relevant quotes from his
Institutes with my own comments.
Every individual mind being a kind of labyrinth, it is no wonder, not only that each nation has adopted a variety of fictions, but that almost every man has had his own god. To the darkness of ignorance have been added presumption and wantonness, and hence there is scarcely an individual to be found without some idol or phantom as a substitute for Deity. Like water gushing forth from a large and copious spring, immense crowds of gods have issued from the human mind, every man giving himself full license, and devising some peculiar form of divinity, to meet his own views...
...If men are only naturally taught, instead of having any distinct, solid, or certain knowledge, they fasten only on contradictory principles, and, in consequence, worship an unknown God. Hence we must hold, that whosoever adulterates pure religion (and this must be the case with all who cling to their own views), make a departure from the one God. No doubt, they will allege that they have a different intention; but it is of little consequence what they intend or persuade themselves to believe, since the Holy Spirit pronounces all to be apostates, who, in the blindness of their minds, substitute demons in the place of God. For this reason Paul declares that the Ephesians were “without God,” (Epheisans 2:12), until they had learned from the Gospel what it is to worship the true God. John Calvin, Institutes Book I.V.10
Calvin speaks most clearly here about the human condition. Summarized often as "Total Depravity". (Great name for a [non-Christian?] ska band!) We, without God, have no idea how twisted our minds really are, and yet we show so much undue respect and pay so much undue honor to science, education, learning, business, talent, creativity, etc., etc., etc. Not that we should show disrespect or dishonor these fields, but that we should realize that at any point it is likely that human accomplishment may "worship an unknown God" and at the same time "make a departure from the One God."
[Persons] have in their own persons a factory where innumerable operations of God are carried on, and a magazine stored with treasures of inestimable value—instead of bursting forth in his praise, as they are bound to do, they, on the contrary, are the more inflated and swelled with pride. They feel how wonderfully God is working in them, and their own experience tells them of the vast variety of gifts which they owe to his liberality. Whether they will or not, they cannot but know that these are proofs of his Godhead, and yet they inwardly suppress them. They have no occasion to go farther than themselves, provided they do not, by appropriating as their own that which has been given them from heaven, put out the light intended to exhibit God clearly to their minds. At this day, however, the earth sustains on her bosom many monster minds—minds which are not afraid to employ the seed of Deity deposited in human nature as a means of suppressing the name of God. Can any thing be more detestable than this madness in man, who, finding God a hundred times both in his body and his soul, makes his excellence in this respect a pretext for denying that there is a God?John Calvin, Institutes Book I.V.4
Total depravity is shown to be the totality that it is. Where we have been created in glory and majesty and honor (
Psalm 8) we have traded that glory for ignorance of the One Creator Lord. "How majestic is Your name in all the earth." Instead of "living up to our potential" (or "living before our potentate") we live
down to our "monster mind", which intently destroys and dis-recongizes God in all arenas of its life.
This, however, I the closest that Calvin comes to saying "idol factories."
The human mind is, so to speak, a perpetual forge of idols. There was a kind of renewal of the world at the flood, but before many years elapse, men are forging gods at will... The human mind, stuffed as it is with presumptuous rashness, dares to imagine a god suited to its own capacity; as it labors under dullness, nay, is sunk in the grossest ignorance, it substitutes vanity and an empty phantom in the place of God. To these evils another is added. The god whom man has thus conceived inwardly he attempts to embody outwardly. The mind, in this way, conceives the idol, and the hand gives it birth. That idolatry has its origin in the idea which men have, that God is not present with them unless his presence is carnally exhibited, appears from the example of the Israelites: “Up, make us gods who shall go before us. As for this Moses, the man who brought us up out of the land of Egypt, we do not know what has become of him." (Exodus 22:1). They knew, indeed, that there was a God whose mighty power they had experienced in so many miracles, but they had no confidence of his being near to them, if they did not with their eyes behold a corporeal symbol of his presence, as an attestation to his actual government. They desired, therefore, to be assured by the image which went before them, that they were journeying under Divine guidance. And daily experience shows, that the flesh is always restless until it has obtained some figment like itself, with which it may vainly solace itself as a representation of God... After such a figment is formed, adoration forthwith ensues: for when once men imagined that they beheld God in images, they also worshipped him as being there. At length their eyes and minds becoming wholly engrossed by them, they began to grow more and more brutish, gazing and wondering as if some divinity were actually before them. It hence appears that men do not fall away to the worship of images until they have imbibed some idea of a grosser description: not that they actually believe them to be gods, but that the power of divinity somehow or other resides in them.Institutes Book I.XI.8-9
Our hearts are not "perpetual idol factories" exactly. The idea is there, our desires, wants, and passions, always seeking after other gods. So, with
Jonathan Edwards, we must be dilligent in forming our passions towards the One true God. However, Calvin seems to indicate that it is not passions that must be formed first but our perception of God in our thoughts first. A correct thinking about God, will result in a correction worship of God.
So where the idea of "idol factories" is sound, it would seem that its usage is incorrect. Calvin wants us to have a correct and pure view of God (a God who is Spirit, and cannot be served or fashioned by human hands). A corrected (opened?) mind will lead its heart towards the proper affections.
It think this is reflected in the first two commandments. We are to "worry about" worship second, only after we have a right view of God. "You shall have not other God's before me" or in the Hebrew "You will not have any other god in my face." God doesn't want us to even see any other god, but for us to see Him and him alone. Only then will we be able to properly worship (the second command).
Anything "worshipped in place of God" is sin. But I don't think this is Calvin's point. I think that Calvin is warning not to trust our hearts at all, depravity is total. He might even be leery of our evangelical talk about "putting God on the throne of our heart." He might even warn that because our hearts/minds are idol factories/forges, even this (well intentioned and seemingly innocuous) is dangerous. Or I might just be putting words in his mouth.
Our minds all too easily place something on our heart's throne and we call it "god." When in reality what we do is [commandment 2!] fashion and bow down to it.
Seeking the One God in scripture and prayer and (more scripture and prayer) will naturally reveal to our monster minds that power of the divine is not ours to randomly move about at will. Only God is God [commandment 1!]. The divine lies only in Him and is not something that our hearts can comprehend. He must rescue us from slavery... [commantment 0!]
Romans 7:24