Attributed to Immanuel Kant, the critical philosophy (German: kritische Philosophie) movement sees the primary task of philosophy as criticism rather than justification of knowledge; criticism, for Kant, meant judging as to the possibilities of knowledge before advancing to knowledge itself (from the Greek kritike (techne), or "art of judgment"). The basic task of philosophers, according to this view, is not to establish and demonstrate theories about reality, but rather to subject all theories—including those about philosophy itself—to critical review, and measure their validity by how well they withstand criticism.
"Critical philosophy" is also used as another name for Kant's philosophy itself. Kant said that philosophy's proper enquiry is not about what is out there in reality, but rather about the character and foundations of experience itself. We must first judge how human reason works, and within what limits, so that we can afterwards correctly apply it to sense experience and determine whether it can be applied at all to metaphysical objects.