For Karl Barth it is a frivolous pursuit to attempt to psychologize a theological anthropology, and yet in the Tradition (both Roman Catholic and Protestant) this is exactly what has obtained. For the Western tradition the appeal, particularly for Post-Reformation scholastic theologians was to appeal to an Aristotelian understanding of what it means to be human; an appeal to what has been called a faculty psychology (i.e. affections, intellect, and will)–we see this approach in Augustine, Medieval theology in general, Thomas Aquinas, et al. As Barth engaged with various post-Reformed theologians, like Amandus Polanus he was pushed up against this reality; and he rejected it (and I would add: rightly so). Here is Reeling Brouwer describing Barth’s engagement with Polanus’s theological-anthropology (and as you read this you will see that Brouwer quotes Barth directly as well – this quote from Brouwer comes from the context of him discussing Barth’s engagement with Polanus’s doctrine of creation):
For the second issue, namely man, Polanus does not divide the material into a dichotomy. Instead he works – as he does more frequently – with the Aristotelian division into definitio (hominis) [V. 27], causa efficiens [V. 28], materia [V. 29 – 31], forma [V. 32], and finis [V. 33]. Here the body is, of course, the matter, and the soul the form of human being. Barth addresses Polanus’s definition of man in the paragraph entitled ‘Phenomena of the Human’. This is already an indication of his objections to this definition. Although Polanus qualifies it (after the analysis of the nomen) as the beginning of a contemplatio theologica hominis, Barth cannot see the real theological point in this definition and considers it to be a description of the mere phenomenon of a human which nevertheless does not point to the real man. He writes:
Polanus opens with the [in Barth’s eyes] clear-cut Aristotelian definition: homo est animal ratione praeditum. He explains it as follows: [definitio haec duabus partibus constat: genere & differentia specifica:] ‘man belongs to the genus animal, that is he is a substanti corpore organico et anima vegetante atque sententie & loco movente constans’ [Polanus refers here to Gen 2,7 and 1 Cor 15,46 – 47]. The differentia specifica from other animals is that he is gifted with reason. By this we are to understand the vis intellectus, qua is logizetai, ratiocinatur et [ut Scholastici loquuntur] discurrit, hoc est ex uno aliud [deducit] vel aliud post aliud ordinat. Hence the opus seu officium of reason consists in discursus, i. e. in the swiftness [celeritas] with which his mind moves from one thing to another, from causes to effects, from effects to causes, and therefore to the knowledge of all things. This vis intellectus is not given to any other animal….
It is indisputable, Barth comments, that one here sees a phenomenon of the human. But the definition is already doubtful from a philosophical point of view and still more so with regard to its theological quality. What is the relationship between this result of (classical Greek-dualistic) human self understanding, namely an understanding of man’s own vis intellectus, and the knowledge of God as a knowledge of the covenant (in the sense of the opening Chapter of Calvin’s Institutes)?…
What we see in this development of Brouwer, and in Barth’s critique of Polanus, reflects a very typical Western analytical development of what constitutes what it means to be a human being (i.e. anthropology). We also see Barth’s critique of the received Aristotelian intellectualist anthropology that sees the defining component for what makes a human, human over-against the other ‘animals’, is that humans have intellect and the ability to self-reflect, not only upon themselves, but upon God. Barth sees this as a very speculative way to conceive of humanity, as a philosophical convention that has nothing to do with theological development; and almost nothing to do with what he thinks philosophy (in the analytic tradition) has real access to. As we close the quote from Brouwer, he makes clear that Barth thought that a genuine theological anthropology could only delimit itself to the covenant; of God become man, and in Christ man exalted to participate in the ‘divine nature.’ But what does this mean for Barth?
Karl Barth in his little book The Humanity of God answers for us how humanity ought to be conceived of from within covenantal terms, from within a Calvinian focus wherein knowledge of God provides for a genuine knowledge of what it means to be human; and of course for Barth this is grounded in the nexus of the only place that that reality has happened, in Christ (Logos ensarkos):
In Jesus Christ there is no isolation of man from God or of God from man. Rather, in Him we encounter the history, the dialogue, in which God and man meet together and are together, the reality of the covenant mutually contracted, preserved, and fulfilled by them. Jesus Christ is in His one Person, as true God, man’s loyal partner, and as true man, God’s. He is the Lord humbled for communion with man and likewise the Servant exalted to communion with God. He is the Word spoken from the loftiest, most luminous transcendence and likewise the Word heard in the deepest, darkest immanence. He is both, without their being confused but also without their being divided; He is wholly the one and wholly the other. Thus in this oneness Jesus Christ is the Mediator, the Reconciler, between God and man. Thus He comes forward to man on behalf of God calling for and awakening faith, love, and hope, and to God on behalf of man, representing man, making satisfaction and interceding. Thus He attests and guarantees to man God’s free grace and at the same time attests and guarantees to God man’s free gratitude. Thus He establishes in His Person the justice of God vis-à-vis man and also the justice of man before God. Thus He is in His Person the covenant in its fullness, the Kingdom of heaven which is at hand, in which God speaks and man hears, God gives and man receives, God commands and man obeys, God’s glory shines in the heights and thence into the depths, and peace on earth comes to pass among men in whom He is well pleased. Moreover, exactly in this way Jesus Christ, as this Mediator and Reconciler between God and man, is also the Revealer of them both. We do not need to engage in a free-ranging investigation to seek out and construct who and what God truly is, and who and what man truly is, but only to read the truth about both where it resides, namely, in the fullness of their togetherness, their covenant which proclaims itself in Jesus Christ.
Barth still has a focus on ‘knowledge’ as the ground from which man can come to know what it means to be human, but unlike the scholastics (Polanus, et al.) Barth’s approach was not to interiorize this by focusing on various components of what might make man, man; instead Barth takes an exteriorizing approach that simply attempts to think from within the covenant that God established between Himself and creation, in general, and humans in particular, with His life in the Son (the One who elected our humanity for Himself) as the inner ground of the external reality we see and experience in the created order.
What we see in Barth, then, when it comes to developing a theological-anthropology is a principial Christocentric concentration wherein philosophical and psychological speculation is thrown out the window, and concrete theological theoanthropology is conceived of by inhabiting the reality of Bethlehem.
 Rinse H Reeling Brouwer, Karl Barth and Post-Reformation Orthodoxy (Farnham: Ashgate Publishing Limited, 2015), 64-5.
 See John Calvin, Institutes 1.I: ‘Without knowledge of self there is no knowledge of God … Nearly all the wisdom we possess, that is to say, true and sound wisdom, consists in two parts: the knowledge of God and of ourselves. But, while joined by many bonds, which one precedes and brings forth the other is not easy to discern. In the first place, no one can look upon himself without immediately turning his thoughts to the contemplation of God, in whom he “lives and moves” [Acts 17:28]. For, quite clearly, the mighty gifts with which we are endowed are hardly from ourselves; indeed, our very being is nothing but subsistence in the one God. Then, by these benefits shed like dew from heaven upon us, we are led as rivulets to the spring itself. Indeed, our very poverty better discloses the infinitude of benefits reposing in God….’ (p. 35-6, McNeill).
 Karl Barth, The Humanity of God (Atlanta: John Knox Press, 1978), 46-7.