The truth of the matter is a little different.
The following is from Mike Horton's essay in Beyond the Bounds. Not only is this a very fine book, but it is even worth buying for the sake of this one essay.
Contrary to popular caricature, Reformed scholasticism championed an anti-speculative and anti-rationalistic theological method based on the Creator-creature distinction. Turretin, for example, speaks for the whole tradition when he states:
But when God is set forth as the object of theology, he is not to be regarded simply as God in himself...but as revealed...Nor is he to be considered exclusively under the relation of deity (according to the opinion of Thomas Aquinas and many Scholastics after him, for in this manner the knowledge of him could not be saving but deadly to sinners), but as he is our God (i.e., covenanted in Christ as he has revealed himself to us in his word).Even sola scriptura is not some abstract notion of authority imposed on theology from without, but is the recognition that, as the Reformers so clearly warned, the knowledge of God in his blinding majesty is deadly, while the knowledge of God in his condescending self-revelation is saving. Turretin elaborates on the contrasting approaches:
Thus although theology treats of the same things as metaphysics, physics and ethics, yet the mode of considering them is far different. It treats of God not like metaphysics as a being or as he can be known from the light of nature, but as the Creator and Redeemer made known by revelation...For theology treats of God and his infinite perfections, not as knowing them in an infinite but in a finite manner; nor absolutely as much as they can be known in themselves, but as much as he has been pleased to reveal them.Michael Horton "Hellenistic or Hebrew? Open Theism and Reformed Theological Method," in Piper, Taylor and Helseth, Beyond the Bounds: Open Theism and the Undermining of Biblical Christianity, p. 205-6