I once wrote something on Barth’s view of philosophy (actually more than just once). Barth, in summary, saw value in philosophy, but only in a horizontal sense; and more negatively with its illustration of how impotent it actually is when attempting to think divine things. In a note on Friedrich Schleiermacher’s Christian Faith one of the editors (i.e. Tice, Kelsey, or Lawler) offers insight into
Schleiermacher’s view on philosophy; interestingly it sounds very similar to Barth’s. While Barth, as we know by now, was critical of Schleiermacher, and the tradition Barth perceived him to represent, he was also of a kind in certain sensibilities. Here I think both Barth and Schleiermacher were of a piece in the sense that they wanted to smash any notion that speculation about God could accomplish anything of ultimate value. The editors write of Schleiermacher in the Christian Faith:
In tightly outlined fashion, this entire subsection borrows from conceptual structures prominently contained I Schleiermacher’s philosophical work, including especially his philosophy of mind and action (psychology and ethics) and his dialectic (including epistemology, metaphysics, and logic). Every claim made, therefore, has been examined and scrupulously set forth there. The question thus arises as to how he can, at the same time, claim that philosophical content does not belong in a presentation of Christian doctrine and, nevertheless, do such borrowing from his philosophical work here. Although this subsection does not directly address this question, its content is, in part, self-answering. That is, just as the material presented in the Introduction openly borrows from philosophy but does not claim to be doctrine, so too, Part One contains conceptual structures that help to frame his discourse, but he claims no more for these presupposed conceptual structures than that the reader weigh whether, and to what extent, two tasks he sets forth matter. The first task is to weigh which of these presupposed conceptual structures are pertinent to an actual presentation of doctrine. The second task is to weigh which, or all, of them are to be “presupposed” in Christian religious self-consciousness in our own time and place—on “real,” not merely “notional,” grounds. This second task would be conditioned on what philosophy and science can be taken to provide thus far to help us examine what can occur within our own “real” world. Among these presuppositions are claims that pragmatic theories would assert today (e.g. the impossibility of absolutely certain knowledge and the ever-present admixture of error in comparatively valid truth claims, and future confirmation or disconfirmation of such claims as empirically grounded theoretical and practice-oriented work continues). Moreover, some scientific observations and theories, which he relied on or foresaw, he thought might well be consistent with particular scientific and philosophical examinations of “reality” up to now. For example, his sense that if God cannot be known in se, there is evidence in faith-based experience that God does, nevertheless, reveal something of God’s creative, sustaining, and redemptive work in this “real” world, and that this inspiration and revelation can sufficiently inhabit the feelings and perceptions, and the thinking and doing of human beings, to be found among members of Christian communities of faith.
Such presupposed conceptual structures, he believed, can help Christians in the process of coming to understand and improve upon their own “faith” experience (cf. Anselm’s Prosologian, from which this work takes its motto: “faith seeking understanding”). However, as beliefs, whether firmly or tentatively held, they are not identical with that faith. Like all scientific or philosophical claims in other domains of investigation, they are to be constantly subject to critical investigation and consequent change. Nevertheless, in his view, if they come to us wholly from outside Christian experience of God’s grace through faith, they must not be allowed to intrude upon doctrine that can validly claim “reality” for such Christian experience and explain why to persons of faith. This approach, taken in all his works, emphasizes a critical realist mode of proceeding. Schleiermacher deemed this approach to be most desirable for all “science,” including those more philosophical or more theological in character.
Finally, as Schleiermacher indicates and demonstrates in numerous of his writings, should there ever be a τέλος (final end, consummation), it would be one in which the findings of reason and those of faith and religious doctrine would cohere. Hence, even in his time he did not fear that faith or genuine faith-doctrine would necessarily be endangered by any progressive findings of science or philosophy. Meanwhile, some folks are bound to disagree.
Philosophy, for Schleiermacher (as for Barth), is something that happens “out there,” and it offers relative value and insight to the human predicament in certain qualified ways. What philosophy can’t do, precisely because of its speculative and horizontal-bound nature, is provide a solid foundation for the Christian theologian to practice their craft towards knowing God. In their respective ways, Schleiermacher and Barth, maintain that the theologian’s ingression for accessing God can only be God. How they arrived at the basis upon which the theologian can work from a non-speculative posture was disparate, to an extent. But they both saw Christ central to the theologian’s grounding-point for arriving at any sort of accurate knowledge of God. For Schleiermacher this meant that Christ was the point of contact and pinnacle wherein the human-self-consciousness could elevate to the presence of God; whereas for Barth, while the point of contact was the vicarious humanity of Christ, just the same, his emphasis was on the Christ extra nos or outside of us upon whom the human agents are fully and only contingent from moment to moment. In Schleiermacher we might say that we have an interiorizing of this Christ reality, whereas for Barth it is an exterior Christ who comes to us afresh and anew un-predicated upon the human conscious. But these are matters for another post.
Suffice it to say: Both Schleiermacher and Barth were committed to a non-speculative, via positive, kataphatic approach to God. This is in contrast to the sort of speculative theology that Thomas Aquinas and the tradition after him his known for. As such, this Schleiermacherian and Barthian non-speculative approach to theology proper (and the rest of theological task following) offers an alternative mode for doing Christian theology that is seemingly on tap for the masses of Christians who are currently being subjected to the retrieval projects of the various evangelical and Reformed theologians among us. Take heart.
 Cf. Friedrich Schleiermacher, Christian Faith: Volume One, trans./ed. By Terrence N. Tice, Catherine L. Kelsey, and Edwin Lawler (Louisville, Kentucky: Westminster John Knox Press, 2016), 359-60 n.18.