  Soft cosmology is an extension of standard cosmology allowing for a
scale-dependent equation-of-state (EoS) parameter in the dark sectors, which is
one of the properties of soft materials in condensed-matter physics, that may
arise either intrinsically or effectively. We use data from Cosmic Microwave
Background (CMB), Baryonic Acoustic Oscillations (BAO), Supernovae Type Ia
(SNIa), and Redshift space distrotion (RSD) probes, in order to impose
observational constraints on soft dark energy and soft dark matter. We examine
three simple models, corresponding to the minimum extensions of $\Lambda$CDM
scenario, namely we consider that at large scales the dark sectors have the
EoS's of $\Lambda$CDM model (dust dark matter and cosmological constant
respectively), while at intermediate scales either dark energy or dark matter
or both, may have a different EoS according to constant "softness" parameters
$s_{de}$ and $s_{dm}$. The observational confrontation shows that for almost
all datasets the softness parameters deviate from their $\Lambda$CDM values, in
a prominent way for soft dark energy and mildly for soft dark matter, and thus
the data favor soft cosmology. Finally, performing a Bayesian evidence analysis
we find that the examined models are certainly preferred over $\Lambda$CDM
cosmology.
